I got him to fly! Find two blue barrels. Stack one on top of the other. Stand on the pile, then target the bottom barrel in the pile with your gravity gun. Then just slightly lift it in the air, and he'll fly!
Bug: I'm fighting the Tunnel beast. He does his thing where he jumps in the air. Then the battle just sits around from there... nobody is allowed to move anymore.
I found that, playing the fire camp, I couldn't create their highest level unit even though I had all the prerequisite technologies, buildings, and resources to build it. In the training menu, the unit displayed with pictures lit up, like any other unit that could be trained. But when you push the training button and press ok, nothing happens.
Slayzer, remember that you're dealing with uneducated minions. You think they're going to say something that makes sense? If they were that smart, they wouldn't need to steal science because they could just make science!
I made a ship that can't actually be destroyed. I actually thought I drew a little dot, but no ink came on the paper... which means I'm just flying an invisible spaceship. I can run right into enemies without any problem! :P
1/5! I tried to skip the shotgun and just buy the pump gun and some ammo. After I got it, the game started me using the musket (with no bullets), and wouldn't let me switch guns.
I have to go to the bathroom, yet can't because it will surely result in Earth's demise. If only there was a button I could push which would temporarily stop the passage of time within the game while I was able to use the bathroom... hmm...
Dual machine gun and as many damage buffers as possible, with the machine gun in the back. The buffers draw fire away from the machine gun, and your machine gun can do as much as 4 damage per bullet from the start of the campaign.
 "John Citizen"){kind=icon}
 "Sonny 2"){kind=icon}
 "Sagittarius:2172"){kind=icon}
 "Ultimate Crab Battle"){kind=icon}
 "Castlewars"){kind=icon}
 "Swords & Sandals II: Emperor's Reign"){kind=icon}
 "Mastermind: World Conquerer"){kind=icon}
 "Divine Generals"){kind=icon}
 "The Several Journeys of Reemus: Chapter 2"){kind=icon}
 "Doodle Defender 2"){kind=icon}
 "Damn Birds"){kind=icon}
 "SeppuKuties"){kind=icon}
 "Squiggle Squid"){kind=icon}
 "Doomed Earth"){kind=icon}
 "StormWinds 1.5"){kind=icon}
 ":the game:"){kind=icon}