It's fine, though as other replies say, the rules may not be very obvious. In mode 1 I am unsure how I won, since I always saw ~400/800 objects in the world. It seems in retrospect it's the size of thing I'm merging that determines the win state. Mode 2 was pretty much impossible to beat (as promised?).
Anyway, it works, has good on-screen assistance, is responsive aside from some slowdown during the initial spawning phase. Not bad for vibe coding!