Hoping Cuatic Games hotkeys 'n' to next wave so you don't have to click on the button, which helps you keep your gun aimed at the baddies. Vote up if you agree.
The damage upgrades to the gun don't upgrade its damage - you can test this on those little purple bugs from level 1 on, which always take two shots to kill, no matter how upgraded you are.
To anyone who's running out of skill points: quit (and save), then load. When you reload the game, you'll be able to spend a skill point again. You can repeat this until you've spent all of your points on whatever you like. The only constraint is that you can't spent on units not in the current battle.
Chapter 3 is impossible, right after you jump off the cliff your only options are go underwater and drown or try to jump to the left, hit your head on an invisible ceiling, and fall into the water.
Is Target Time actually possible? I can't do any other missions as people seem to be suggesting, it's the only one available. All I have is a laser scoped pistol with extended magazine; with or without steady hands, the level seems to be pretty much impossible.