So this one of those "murder simulators" newgrounds is famous for?
Seriously though, this game's fun. Simple yet very entertaining. Feels like a more cutesy pixel version of the original Postal. I love it.
And like it's already been said below, it could totally expanded on with more levels/maps, in-game challenges, maybe even extra player characters with different gamestyles. But as is, it's already a great game, especially for having been made in three days. Amazing job.