Super cute!
I liked the idea of cleaning to make the nights easier, but the way the weapon worked it didn't feel like it made much of a difference as long as the monsters were clustered together. If you were to continue developing this I would make the impact of not having cleaned up enough more severe. Maybe you could get fired for not keeping clean? Then clustering the enemies during the night in order to make cleaning easier like another commenter mentioned would be more important.
Cheers! :)