Very nice, I love it so far and the idea of this. Your title of this post really made me laugh btw and I cant believe it's really named after that famous line from Predator lol.
You should do an arcade mode for this. Something similar to Xevious, where enemies come from the corner of the screen or so and try to shoot the player down with a nice boss at the end of course. And last, maybe a co-op mode where two players can both do arcade mode together if that won't be too much for you. The enemies can just be basic grey color jets/helicopters or any color really except the colors you have for the players.
Thank you! I currently plan to add a simple survival mode that can be played alone or co-op. I would like to add an arcade mode in the future, but it is a project that I carry out in my spare time... so I don't know when that would be... also along with the survival mode I will add power ups in the multiplayer and variety on the map and the terrains in the next update :).