Project B comment:
I think the game is way too simple. Since there is no progression and the player is just supposed to kill as many monsters as possible, it gets boring quickly. I can just stand in front of one monster and kill it when it respawns and farm points. Maybe it could be nice to give some kind of combo bonus when killing a lot of monsters in small time frame. Or maybe it could be something like time rush where you have to kill all the monsters as fast as possible.