The thing is, you can play it in any way you like. You don't have to optimize for speed at all if you don't enjoy it
I'd kill to be able to build my own small helper libraries in something like Exapunks, but that's way beyond the scope/flavor they were shooting for. I do think there's a neat game there where you setup different problems in a way so naive coders find out their abstractions/libraries aren't perfect (what do you mean i got a null?), but obviously that's a different game at that point.