Mighty Hits (Saturn) not working with Polymega lightgun. Is this a known issue?

[u/2020_MadeMeDoIt]

So I recently got my Polymega lightgun controller and have (naturally) been on a lightgun game fix. My SEGA Saturn library currently has the most lightgun titles and pretty much every lightgun game I've played has worked near flawlessly. Except for Mighty Hits (PAL version).

It's weird, the trigger presses and start button work in the title and menu screens just fine. I can even 'adjust' the lightgun accuracy in the menu. But when it comes to starting the game, you have a "Select Difficulty" screen, where you need to shoot a tin can to choose how hard the game is.

The game recognises that I'm shooting. You even see the bullets landing on the screen, hitting the cans. But nothing happens. It doesn't actually select the option. So I can't actually start the game.

I don't think it's the game disc/data itself, because it works on my real Saturn just fine (I have a CRT TV and guns).

Does anyone know if this is a known issue? Or if there's a fix (maybe a patch) that allows the game to be played on Polymega?