Nice idea, you managed to implement a simple shooter concept but with a unique twist, I like that the characters stayed on the map when you switched, meaning you still had to protect them.
However, the visuals are very bland, I feel like this game would have been better off in a 2d environment since you only used 2 dimensions and you would have been able to implement details easier. Some sounds would have been nice as well. Also, when I moved to far out, I fell off the map but nothing happened, maybe some sort of respawn would have been nice.