Trench Defense
They don't stop. They don't sleep. One trench, a few towers, and your nerve.
Dig in with WWI machine guns, dig out with future-tech turrets, and hold the line while the AI probes every weak point you left it. Pathfinding enemies find the gap you didn't think was a gap. Status effects stack. The next wave is always worse than the last one, and that is the point.
It started life on Roblox and got rebuilt in Flutter once it outgrew that. I'm building this one with my kid, which makes it the most important thing on this list for reasons that have nothing to do with the game. The game is half of it. Building it together is the rest.
Playable in a browser. Unfinished like everything else here, and the balance is the part most worth arguing with me about.