i dont know if its just the demo version but....
1) there is no hp bar for any of my units. that is one thing i personally like. because then i can better plan WHEN to repair.
2) there is no countdown until round is done. i dont know when it will end.
3) have the jets go a little slower, or keep them from coming from odd directions. i had 5 sam sites evenly spaced out and 2 jets went by because of the angle they came at. It is a terrible weakness for the sam sites. i think each one might have hit the jet once out of atleast 10 shots.
4) more upgrades. however thats probably in full version XD