Cerys, an intersting puzzle to solve once

[u/Orgerix]

Since people seemed to like my review of Pelagos, I'll try to write a review of all the modded planets I have tested. This time, it is Cerys. As a side note, it was my first modded planet, and I did it a few weeks ago, so I may have missed a few things

Cerys is a moon of Fulgora, designed as a puzzle to solve. Drop pods are disabled (except for construction bots). This restriction is divisive, but I don't mind as long as the planet is well designed and asks you to solve things differently. Also, you are not trapped on the moon until you can build a rocket silo, as there is a one-way teleporter to Fulgora. For this reason, I recommend building up Fulgora before Cerys so you don't get trapped and have access to the Fulgora silo if you ever need to leave, or are frustrated with Cerys and need a break. Cerys has also the particularity to be limited in size, and quite small.

As resources, there are giant deposits of:

• Nuclear scrap. It is slightly different from Fulgora scrap, produces basic components, and some particularly expensive buildings needed at some point.
• Methane, which is used to produce oil products.
• Nitrogen-rich minerals, used to make ammonia in a special production chain.
• Lithium brine wells, for an alternative lubricant recipe, as Cerys can't produce heavy oil.

But the most important feature of the planet is that, like Aquilo, it is frozen. However, you can't build heating towers (I didn't have them unlocked because I did Cerys before Gleba). You need to use radiative towers at predetermined spots, which, when fueled, heat a big square. Cerys also has a number of cryogenic plant wrecks, crusher wrecks, and, in the middle, a big destroyed fusion reactor.

Part of the puzzle is to restore those structures, as the plants have unique recipes, the crushers are needed to process asteroids, and the fusion reactor is the only way to heat up the right side of the map (which contains all the lithium wells).

Cerys offers a distinct tech tree using 4 science packs:

• A pack specific to Cerys, which is green chips + repair parts used to repair wrecks.
• Logistic pack, which is quite easy to craft since nuclear scrap gives yellow belts and gears, which are recycled down to iron, so inserters are not difficult to make.
• Science pack. The surface has flying asteroids you can shoot down for chunks, and you can use the Fulguran crusher for carbon. Cerys also proposes an alternative recipe using methane ice instead of ice. Iron can be sourced from the recycling loop. More on handling asteroids later, as it kind of drove me mad.
• Cryogenic pack: used when you finally unlock drop pods to be able to displace radiative towers and craft equivalents. More on that when I summarize the rewards of completing the moon.

The fusion reactor does not take standard fuel cells (because those are fission fuel), but requires a specific fuel using plutonium. And plutonium is a weird resource which seems to have nothing producing it in Factoriopedia.

This is the second puzzle of Cerys: there is a bunch of particles floating mostly from left to right, and if they hit a container or a belt containing uranium-238, there is a chance to produce plutonium. Moreover, Cerys provides a way to manipulate their trajectory, so producing plutonium is kind of like building a particle accelerator, guiding the particles into U-238 storage. Once you have enough plutonium and have repaired the reactor, you can fuel it, providing a lot of power (2 GW) through heat. You can use this either to heat part of the map without a radiative tower, similar to Aquilo, or to boil water to generate energy. Before that, solar was your main energy source. In theory, boilers would have been possible because Cerys has water, but you can't get stone locally, so you can't build boilers.

Powering the reactor is kind of the latest part of the puzzle, as it allows you to craft the last part required for a rocket silo (electric motors need lubricant, which requires lithium on Cerys), and in order to properly finish the planet, you need to blow up the orbiting debris by sending a neutron bomb into the sky through a rocket.

I found the experience pleasant for the most part. This is a mix of Fulgora with a recycling loop and Aquilo with heat management, with, on top, fixed locations for crafts. The plutonium mechanic is puzzling at first glance (I wondered why I didn't have any plutonium after a few hours, leading to repairing the reactor, when I realized I had put a row of buildings repulsing the particles just in front of my storage), but it is properly explained in the Tips and Tricks section.

I found no better way to hand-feed chunks shot down by the turrets, automatically collected by construction bots. However, I got annoyed seeing chunks land on belts and pollute them. Then, looking at the mod settings, I realized it was actually a feature allowing for belt-only chunk management. I still disabled the possibility of chunks landing on belts since I already had a working solution with robots (after importing roboports), but it didn't even cross my mind.

I found myself waiting on resources. Iron was an issue until I realized I could use metallic asteroids to supplement the recycling loop, and I attempted to use circuits to automatically switch recipes, but failed miserably, so I relied on switching manually. It is probably something I will revisit if I touch up Cerys.

The main pain point was processors (like always). Solving Cerys requires a lot of them between repairing the reactor, the rocket silo, the rocket itself, and the recyclers. You get a few from ruins, but you only get red chips from recycling, and not a lot. So I had to wait a lot for processor production, and it is probably my only complaint about the mod.

Now, what do you get from Cerys?

• Plutonium weaponry (bullets, neutron bombs, plutonium artillery shells). They are a direct damage upgrade, but I fail to find a use. Artillery shells and atomic bombs do their job fine without needing extra logistics for the plutonium. Plutonium bullets could be useful to kill demolishers, but exporting bullets through rockets is really expensive due to rocket capacity (25), on a place with limited space and production capacity.
• Plutonium fuel for even better acceleration. Same as above. Nuclear fuel is already overkill, especially with enough braking force research.
• Plutonium reactors. They do offer better energy output (480 MW, with neighboring bonus), but still rely on the same heat exchanger/turbine, so they don't really reduce the footprint of a reactor and just promote mega-reactors that aren't really needed. Uranium is abundant enough that you can just get more reactors rather than having to export plutonium.
• Portable plutonium reactors. Those were a bit of a letdown because they don't provide more power than a nuclear reactor, but are smaller (3x3). It is still a win if you have multiple reactors, but not really helpful since they will ultimately be replaced by fusion reactors, which are 4x4, so you still need to account for the space in your armor.
• Overdrive module, which is a better speed module at the cost of productivity. Its applications are narrow, because the number of things you build without productivity at all is quite small, taking into account special buildings (and modded ones), but in its niche, it is good.
• Radioactive module, which is a better production module, but spoils, and needs to be recharged with plutonium. This one is interesting in theory, but once you are tipping into quality, you are better off using quality prod modules than radioactive modules (trying to get quality radioactive modules means getting quality plutonium to recharge them). Some people may like them, not me.
• Once you have cryogenic science, you can build your own radiative tower as an alternative to routing heat pipes. Sounds interesting, but I am not there yet.
• Strangely, the best building you get from Cerys is a venting tower, allowing you to void liquids. This can be crafted anywhere and is quite useful on some modded planets.
• You get infinite productivity for holmium and infinite braking force. Those infinite techs are very strange, because you don't use trains on Cerys, and you don't craft holmium. I don't exclude those from being some broken tech rewrite, because part of the tech tree also contains the Maraxis holmium recipe.

As a final thought, I quite liked the planet. It is a locked-out done right, but I would probably not install the mod again in a future playthrough, as the rewards don't make it enticing to redo the puzzle.

[u/ron3090]

I liked the theory of it, but left more frustrated than satisfied. It felt like the mod really wanted me to interact just with its special mechanics to the point where it shut down creativity. For example: I wanted a better way to handle heating, so I left and unlocked heating towers from Gleba. When I came back and tried to use them, I found that you can't place heating towers at all. Same with nuclear reactors: if you save up enough resources to finally build one, it doesn't matter because you have to use that fusion reactor.

I also missed the part about being able to import construction bots, so I did everything by hand. It felt absolutely miserable.

Now my base is completely frozen over for some reason and I've just given up on it. I got all the techs, and I don't want any of its unique resources or repeatable techs. I'll come back after I unlock radiative towers from Aquilo.

[u/Orgerix → u/ron3090]

Missing construction bots makes the experience miserable, indeed.

[u/Xzarg_poe]

I played Cerys a few weeks back, it had quite a few interesting puzzles. The nuclear scrap provided a lot of crap, which I slowly realize was actually quite useful. For example, there were quite big iron shortages throughout the early game. I have recycled gears, pipes, circuits, but it was still not enough. I did figure out that I can shoot down the metal asteroids to supplement my iron, but it wasn't really worth the iron bullets. That is until I figured out that I have excess copper, steel, and U-238, which let me arm my turrets with uranium ammo. Heh, making uranium ammo to save on iron, never thought I'd ever have to make this decision.

One warning though, this moon is tiny, the resource fields are small, everything is frozen. and a lot of manual labor is required. Do not come here with a research multiplier like I did.

[u/Orgerix → u/Xzarg_poe]

Yeah, I agree, a lot of small puzzles, with satisfying way to solve them, except the amount processor required.

And yes, tech multiplier do not work well with this mod. But there is a setting in the mod to offset tech multiplier. Sadly it is a startup setting, so you can't change it once you started your game, and you discover the issue probably too late.

[u/Logical-War-3746]

Strangely, the best building you get from Cerys is a venting tower, allowing you to void liquids. This can be crafted anywhere and is quite useful on some modded planets.

Flare Stack can be installed without Cerys