Can you add endless mode: no win, you can only lose and enemies are always the same (like 75% chance of spawning normal zombie, 10% to spawn skeleton, 10% to small zombie and 5% to spawn big one);
Maybe hard mode,
food storing,
simple crafting, because wood is kinda useless (I won this game without placing any wood, I was just mining it idk why),
every enemy recives difrent score
zombies after the wave will not barelly disapear, just starts getting damage and lowers poits after killing it (like it counts damage that you deal) and skeletons don't take any damage
you can attack with whatewer you want,
more blocks,
random terrain generator,
doors (they switch bettwen tangible and intagible),
inventory, storage blocks;
enemy loot,
bullets more visible