The game has really nice music, enthuastic and happy tone, pretty good and fitting for the theme and has a nice aesthetic visuals, simple and pretty fun.
Small bugs: the Builderman build ladders even though one is already in its place and consume wood. Small improvement: you can add sound effects when the hammer is swing and the sound when an enemy is dead could be better but still pretty good. You could add a bit more of friction, because when you want to move a bit the character moves a lot compared to the small tap. The hitboxes of the enemies and players should be slightly more smaller, it feels that I'm not even touching the enemies, it should clear that you are really close and that's why you are dead. Sometimes the enemies get stuck into the wall and doesn't move the left and right pattern. And maybe you should add a level selector.
The game is pretty fun, and it can be improved, it would be lying if I didn't say that I had fun with the game.