A good effort. However with the scenery and layout it feels like a game about shooting teachers and kids in a school, so you might want to change that.
To improve I'd suggest some work on the animations, they're a bit slow, with the accuracy perhaps you could have a laser sight or a target cursor move around so the player knows what they'll hit. After i shot everyone, there was nothing left to do but the game carried on.
I look forward to seeing your next entry time.