[armchairhacker]

It’s really nice to see that the solutions they use are really simple.

It seems like no tricky optimizations or complex algorithms, they just tick everything active every frame. The key is that they don’t tick things they don’t have to, and don’t render off-screen sprites, so “ticking” an entity is updating a tiny datastructure and maybe a few other datastructures it points to.

[tomatotomato37]

They do gloss over some RAM/processor cache optimizations near the end that in my experience can get a bit wacky implementing, but yeah seems overall very simple.

I especially like the rule that nothing can exceed O(N)