Interesting! I like the idea of being able to shoot only when near.
Suggestion: The player can just bring two of the characters in one corner and spam the attack button, and since all enemies will pass through that point, the player can break the game like that and easily obtain tons of points. One way to fix this could be to make so the enemies move in different direction so the player can't easily predict the enemy movement and camp in one corner.
Overall I like the game. Great!