Alright, it's been a super long while since I've been able to participate in this, so looking forward to it again.
What comes to mind with this theme is some sort of action game with potentially roguelite or roguelike elements. Like a super lite version of Vampire Survivors, 20 Minutes Till Dawn, something along those lines. Or maybe just a simple twin-stick arena action game. I'll blow my time if I try to focus on doing a lot of those backend systems, so I may opt for something a lot simpler. Maybe skip out the rglt/rglk elements and focus on the action, or try to get at least one element in. We'll see.
I'll try to reuse some really basic code (if allowed), like movement and input, scene management, etc from another project of mine and then try to split my 3 hours this way:
1 hour: Coding Gameplay
1 hour: Art and Effects
1 hour: Polish
Going to aim to have a complete loop, with an intro title, game scene, and results scene, and then return to either the main title or go and play another round. Don't know if I'll be able to implement anything procedural, not that experienced in those kinds of systems.