A very intersting Idea! Reminds me of "This War of Mine" if it was a arcade style arena shooter, (or would it be a shootn't?) I like the art somewhat. The characters look good, but not so much the environments, though it all looks kinda blurry. I like using enemy infighting as a way of combat, I just wish it happened more often. The soldiers seem to spend most of their time walking around instead of shooting or throwing grenades. It's hard to get soldiers to shoot each other when they can only shoot in two directions as opposed to 360 or at least 8. The game feels a little bit too easy because of the lack of actual fighting happening but I imagine it gets harder much later down the line.
All in all I think this is a good concept with some potential, just needs to be more engaging and challenging. 3/5
(Also, protip from one GMS user to another, if you want your pixel art to look less blurry go into the preferences for your game (the button that has three bars and a rectangle on it of some sort), go to window then untick the box that says "interpolate colors between pixels". This will make your game much sharper pixels and it will look better as a result. )