fun way to spens some time, time to make it deeper
a fun and simple game with guns that felt satisfyingly realistic yet where not frustrating to use especially satisfying was the fact that spray and pray wasent a viable strategy but nice controlled burst where.
next time tho I suggest using a building rather then a chopper, it makes more sense repairing it and also adds possibility to make the game deeper by allowing you to "hire" soldiers and a more logical reason to add health increasing upgrades.
As for weapons I suggest adding machineguns too, as well as adding more functional upgrades to the guns like bigger clips or ways to reduce reload time. Also don´t be afraid of stretching realism just a bit and add some weapons that´s more for fun then realism, like a level action rifle or a minigun.
So my final words are, good foundation now it´s all about expanding and improving.