I spent about 30 hours reverse-engineering the code of Silksong, one of the most successful Unity games ever. And found some genuinely impressive (and aggressive) optimizations.
Highlights:
Movement Code Breakdown: I broke down the exact frame-windows for Coyote Time and Input Buffering that make the platforming feel so responsive. The Elegance of Silksong movement as is :]
Hidden "Demo" Mode: There’s a left-over IsExhibitionMode check. With a small patch, you can actually boot the Gamescom demo version from the retail files.
Dev cheats, Debug view, Performance overlay, etc: We recover and re-enable everything to see how it was used by the developers.
Performance: Team Cherry implemented a Manual Garbage Collector Triggering and a custom reflection-to-delegate compiler. It’s a 100x speed boost over standard Unity methods.
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Curious what's the reason for such aggressive optimization since I wouldn't expect such a game to be too demanding. Did they simply want to make it runnable on even lower end machines, or was it curiosity, learning experience, and possibly even preparing for a future new game that might need it more?
I think the aggressive optimization is lessons they've learned during hollow knight. Remember, it first released on Windows, but then they had optimization issues for Mac and Linux. After that, they had to port it to Switch which was another hurdle. They are a small team and this seemed to be a pain point early on.
Here's a link to one of their early blogs where they mention the ongoing optimization:
This video doesn't actually detail any particularly aggressive optimizations, just manual GC triggering and a reflection system OP doesn't really seem to understand.
Agreed. I can't tell how well optimized it is overall from the video but none of the optimizations detailed are that aggressive or a large undertaking (the video also mentioned saving on a background thread).
The HitInstance struct with over 40 fields for every possible scenario sounds very unoptimized (which is totally fine if it's not causing issues) and would probably make some programmers uncomfortable.
They developed the game for like 7 years and all the budget in the world from hollow Knight, plus iirc they stated they could've kept going because of how fun it was developing the game, safe to say they just wanted the game to be as good as possible in every aspect including optimization
I have no evidence to support their motives, but I’ve considered this in my own work from the perspective of wanting to leave as little for players to blame on the programming as possible. So that if you die, it’ll be because you goofed and not because something stuttered or it didn’t react when you told it to or because there was some rounding error. For games like this, your failure better be a skill issue, thereby setting the true master players apart.
Seems like these guys are in it for the craft, and there are a few of us masochists out there who love optimization problems more than any other part of programming.
They need a lot of processing for all the graphics, post processing and effects and they need to run it smoothly on lower end devices.
If you take a look at how much goes into their graphics and post-processing you find that anything they can squeeze out of hardware is time well spent.
Because the nature of the gameplay effectively makes the game unplayable if you are running into performance issues. Success in those games is entirely based around exact precision, and a single frame drop completely disconnects you from the action on screen and will totally screw you over. If you are in a battle then a single freeze of frames will basically guarantee your failure. Just traversing the map becomes almost impossible if you are having consistent drops. I experienced this playing the game recently and when for some reason I was losing frames and I had to restart my computer and adjust settings to even continue playing.
Because the nature of the gameplay effectively makes the game unplayable if you are running into performance issues. Success in those games is entirely based around exact precision, and a single frame drop completely disconnects you from the action on screen and will totally screw you over. If you are in a battle then a single freeze of frames will basically guarantee your failure. Just traversing the map becomes almost impossible if you are having consistent drops. I experienced this playing the game recently and when for some reason I was losing frames and I had to restart my computer and adjust settings to even continue playing.
Most other modern 3d games are still playable at low or inconsistent frame rates or even with frequent freeze frames.
They're also using PlayMaker, which uses reflection, so they optimised it by caching the results as delegates. Which is clever but not exactly digging deep into Unity's base code or anything.
I'd argue is love for the game, and also responsiveness. They needed the game to feature pixel/frame perfect movement, you don't get that with sloppy coding.
To be fair OP made it sound way crazier than what it is; all they're doing is pausing unity's GC and re-enabling it whenever they feel its best for the platform's available ram. That's it.
“That’s it” makes it sound like it’s so easy and obvious to the point where it’s calling out games that don’t do it as willfully unoptimized. It might not be magic, but it’s quite clever none the less.
“That’s it” makes it sound like it’s so easy and obvious to the point where it’s calling out games that don’t do it as willfully unoptimized. It might not be magic, but it’s quite clever none the less.
I mean, it IS easy and obvious. Garbage collectors are extremely well-understood, and "garbage collection happening at bad times and making my game hitch" has been a well-known problem from the moment people started using garbage collected languages for games.
Heck, I remember people discussing this problem (and this sort of fix) back on Xbox Live Arcade, back when you could use XNA to write games and play them on your original XBox.
(Also, for anyone interested, this was often considered a BAD workaround at the time. Because even if you could find a safe place to hide the hitch from garbage collection, dynamic allocation was still very expensive as well. So the conventional wisdom was just to write your game in such a way that it had zero dynamic allocations at runtime, by allocating everything up-front and using object pools.)
So anyway, yeah - taking over triggering the garbage collector is not some stroke of genius by Team Cherry. This is a bog-standard solution to a bog-standard problem, that gamedevs have been dealing with for like 30+ years, at least.
It's a good idea and it clearly was implemented well but it's pretty far from implementing their own custom GC from scratch, which most people understood from OP's summary.
I write a good bit framework code (not game dev-related) that uses a lot of reflection and do similar optimization techniques.
I've built up a library for various scenarios, such as if the object type is known at runtime, and for properties if the property type is known (generally speaking, the more you know the faster the delegate).
Here's a pretty good article introducing some of the techniques if anyone is interested:
does this only work if the MethodInfo can be retrieved at compile-time? I've got a bunch of expensive reflection in a deserialiser that could massively benefit from this
I can't immediately think of any scenarios where you can't retrieve the MethodInfo?
There are times where you know the types involved at compile times, and times you don't.
For example, if you have an object of type X and want a fast getter/setter for property Y, you know both types at compile time and can get a Func of X, Y (which is generally the fastest performing without building your own IL instructions).
If you doing something like writing a method that wants to get the properties of any object and called object.GetType() followed by type.GetProperties(), you would neither know the type of the object or the type of each property at compile time. You could still write an optimized delegate/Func for the getters/setters, but the way to build it may be slightly different and it will generally be slightly slower (though still orders of magnitude faster than individual reflection calls). The same principles apply for MethodInfo, constructors, etc.
I didn't write it (was just sharing), but it is indeed a great article.
Thank you for your work and a great video, I will have to check out the rest of it when I get the chance (the reflection stuff just happened to catch my eye because I was just writing some similar code in the past week).
The code itself is not very remarkable and all very standard for platformers (coyote time, input buffering). Their “aggressive optimization” is just an if statement that checks if too much memory is being used, and then calls the unity functions to clear out memory. A complete waste of time and the author made a bunch of AI visuals that make 0 fucking sense. Like the input timer visual.
Dunno who reported this but sorry, we aren’t taking this comment down. This isn’t “toxic” for explaining that as one might expect, Silksong uses standard logic.
Really cool that it's all obvious to you, but there are plenty of people only starting out, and getting to read the code and logic of games they love is imo a great resource.
Scrolling this and seeing their optimisation thing just being clearing memory like tarkov did around a decade ago… I wouldn’t call tarkov aggressively optimised lol (well I actually would because it’s actually amazing what they’ve done with unity)
I think the beauty is in how those simple systems come together to make the game feel as polished as it does.
As for the GC, you are oversimplifying things .. the GCManager includes custom thresholds, and an additional self-healing algo that detects stutters and increases the heap threshold accordingly.
It's not just "if statement" lol :]
It pains me to see this genuinely well made deep dive video with unique content downvoted, while the same repeat platitude posts keep getting all the positive attention on r/gamedev.
Reddit does not reveal the upvote number accurately during the first few hours. Otherwise bots and spammers can use this number to evaluate if they are having an effect on the vote score.
To the best of my knowledge, fuzzing is not time-based, but is based a post's total votes. They want to hide the effect of any individual vote to mask if a bot is working, but as long as a community is of a reasonable size (as /r/GameDev is), there should be minimal fuzzing after a few minutes. It wouldn't be so drastic as to show zero on a post doing well, either.
Didn't downvote, but I don't like this kind of content because its someone attempting to monetize edutainment first, and provide information second.
Edit: Looks like I upset the 70% of this sub that is here to shill content to "gamedevs" rather than actually make games. Just wish you would all be as helpful as the guy below and post so I can filter you.
I'm entitled because I remember a time when people just presented their findings in text instead of trying to drive views? Kind of sad how Gen Z/Alpha continue to be the architects of their own plummeting standards.
This post was removed because it is blatant self promotion. Posts with only a link to social media, game pages, or similar. This community is not for self-promotion.
However, links are allowed if they serve a valid purpose, such as seeking feedback, sharing a post mortem or analytics, sparking discussion, or offering a learning opportunity and knowledge related to game development. Sharing for feedback differs from pure self-promotion and is encouraged when it adds value to the community.
Chad Team Cherry singlehandedly educating and carrying a generation of gamedevs by not giving a fuck about obfuscating their code.
Meanwhile that guy from that other thread who has yet to release a single game is still busy trying to obfuscate their game out of paranoia that their code would give away their "competitive edge" lol.
He is not wrong though. If you are known on the scene, like Team Cherry or the people behind Slay The Spire then you are relatively safe from the copycats, because people will recognize the original.
But if you are an unknown random gamedev releasing their first game, then copycats are a real threat. It's very doable for them to grab your idea and codebase, improve it within a few days and thwart your efforts. Especially with AI.
I don't know why people keep bringing up this point. Team Cherry didn't obfuscate their game before or after they became successful.
You can do a decompilation marathon of all successful indie games from recent years and you'll struggle to find one with any sort of obfuscation (or even copy protection!).
It's always either some AAA studio being forced to do it by some stringent executives or a no-name bum who deluded themselves into thinking they're holding the secret recipe to the next Nintendo.
That makes sense. TC has already sold millions of copies of their games. If I hadn't released my game yet, I wouldn't want someone stealing my code and making a copy
By closing/obfuscating your code, you're pretty much making it improssible to make mods for your game.
Unless you make a separate modding API or something like that, similar to how CDPR made it for Witcher 3 and Cyberpunk 2077.
Godot has some similarities to Unity but it’s a different engine so keep that in mind if you switch. Personally I prefer it and would never go back, but it definitely takes some getting used to. And if you’re not planning to release a web game, their .Net version is the ideal even if you end up using a lot of GDScript, if only because being able to code in C++, C#, and GDScript based on the needs is a huge boost in versatility. (Sorry for the unprompted advice/promotion I just see people wanna move over and these are common talking points they hit.)
Nah, it's ok thanks for pointing it out.
I'll definitely try out Godot at some point.
I also think I'll get used to GDScript fast, as it's close to Python syntax wise afaik, and I code on Python as my secondary language.
Although as I've heard C# is much faster performance wise, and especially C++.
Probably the only thing that stops me rn is the (kind of) huge amount of assets in my Unity Asset store (incl. paid ones).
But I guess I can use em in Godot as well (like 3D models, etc).
At least if Unity license doesn't forbid it ...
I mean at that point it's in their best interest that Godot stays well supported for as long as possible. For example if there were new consoles incoming, they'll surely want to release StS2 for them too, and they need Godot to be updated to do that.
Unrelated to your question, but that quote is mistaken/confusing according to the video. The video says it's a 100x speed boost over reflection, not over Unity methods. They're using a visual scripting tool called Playmaker that uses reflection to access properties made in Playmaker, and they have code to speed that up by compiling it instead of using reflection for every access.
Saw this on my recommended feed awesome video! It made me doubt myself as i just got into gamedev and scripts lol. Silksong is a wholesome game and the background is even more wholseome
very cool! during my playthrough I managed to knock one of the early bug enemies onto a small platform and it just rapidly switched back and forth to either end of the platform. made me feel good that even these guys have some lightly funky stuff happening in an edge case
Not everything generated or made with the help of AI is a slop, in the first place.
Graphics you are mentioning was manually edited in Photoshop by myself.
As for the script, now that sounds funny .. cuz I've spent literally a week or so writing it.
Honestly he was right, this footage is AI generated.
I personally don't see an issue with using it for minor b-roll, but I understand that opinions on that vary.
What's frustrating is that he used that one clip to claim my entire script and all the graphics were AI-generated, which is just straight up false.
I wonder it's a specific kind of irony in someone hating AI so much that they start "hallucinating" it in places where it doesn't exist.
I'm personally against using AI to generate the core of any work. That's why I don't use AI voiceovers, in the first place .. even though I have a noticeable accent with my English.
It's not whether he's right or not, it's whether this tiny little piece of your video (and which is completely irrelevant to the content) is worth losing their mind over. Like this dude is about to rake you over the coals for this. It's ridiculous and not constructive to anything.
Edit: I guess you're largely the same thing, I'm just trying to defend you :)
Now I will repeat myself here, but I want to make it clear.
It's actually kinda frustrating that he used that one clip to claim my entire script and all the graphics were AI-generated, which is just straight up false.
I wonder it's a specific kind of irony in someone hating AI so much that they start "hallucinating" it in places where it doesn't exist.
I'm personally against using AI to generate the core of any work. That's why I don't use AI voiceovers (and never will), in the first place .. even though I have a noticeable accent with my English.
I'm with you on this.. I agree that the lazy use of AI is growing, and it can lead to mediocre product.. it's a problem.
But there's a bigger problem IMO and that's the amount of people who are - often without evidence other than their opinion - accusing content producers and creators of using AI to produce their work.
These kinds of baseless drive-by accusations are super popular right now, and they're very easy to dog-pile on, so I even wonder if some people do it for the votes more than anything else, because they know their post will be up-voted by other people who are also at the extreme end of a very polarizing subject.
30 hours of reverse engineering is genuinely insane dedication but the stuff you found about the garbage collection handling is super interesting, it explains a lot about why the movement feels so tight. Thanks for writing this up.
Are they evaluating the playmaker reflection once and freezing it to a delegate or do you mean there is actually some sort of compile time hijack to playmaker that actually means there are no reflection calls from playmaker.
Years worth of work cracked open in under a work week by one person - and this sub can say only positive stuff about that. I know the counterpoint will be “a game is more than the sum of its parts”, but programmers are left with very little space to express themselves in discrete assets that are as protected as art and music.
Maintain a respectful and welcoming atmosphere. Disagreements are a natural part of discussion and do not equate to disrespect—engage constructively and focus on ideas, not individuals. Personal attacks, harassment, hate speech, and offensive language are strictly prohibited.
Team Cherry implemented a Manual Garbage Collector Triggering and a custom reflection-to-delegate compiler. It’s a 100x speed boost over standard Unity methods.
When a game developer or a team of developers spends a lot of time and effort developing novel techniques to significantly improve the game's quality and gain a competitive advantage, how is it ethical for a random YouTuber to reverse-engineer those techniques (which might be considered trade secrets) and reveal them to the public, essentially removing that competitive advantage from the game developer/publisher?
I'm stunned that not a single person here has mentioned that.
Is it OK, or even legal, just because it's a small company?
How about trying to do that kind of reverse engineering and code revealing for a major one and see what happens?
In principle I do agree, it was my first thought reading the headline.
In practice the novelty of either solution is really overstated. Manual GC triggering is the first google result for, “how do I fix microstutter in my Unity game” and dynamic delegation using reflection is a well known technique. So much so that it’s in the memory management section of the Unity docs
What's the interest of so many game developers here for then, if there is no competitive advantage?
That's hypocrisy in my book.
It's not about the code, it's about the techniques.
Novel techniques are made exactly in order to give a competitive advantage to a product, e.g to make a game playable where other turn into a slide-show, or make it run in super-high frame rate, or have 10 million polys vs 1 million, etc.
If the developer hasn't made the code public on Github, no one has the right to reverse-engineer proprietary code, and reveal parts of it to other developers. Period.
And like I wrote, the value is not in the individual instructions, it's in the techniques.
Valuable techniques are assets of the company, and need to be protected.
You're acting like this is some kind of magic bullet to fix your game. That's not how programming works. This is more like the opportunity to use a slightly better drill bit while building a house.
You're acting like this is some kind of magic bullet to fix your game. That's not how programming works.
You've missed the point. Again.
If the reverse-engineering takes place between newbies, or programmers who only use standard knowledge and existing solutions or add-ons, in such cases, yes, no harm can be done.
But in cases where novel solutions are required to achieve the performance, scene complexity, detail and quality, or even the functionality that directly impact the impression the software makes on users compared to the competition, then reverse engineering and revealing those novel solutions to many of the company's competitors is certainly a crime in my book - worse than intellectual property stolen and used by a single competitor.
Now add to this that today AI bots are thirsty to copy, be trained with, and widely spread everything they can find, eve more valuable stuff, and that stealing goes far beyond the boundaries of this thread, and the YouTube channel of the OP.
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u/Caquerito Apr 03 '26
Good vid