I first found this game on the freeware game site Gamehippo.com (highly recommended!) and within a few short hours just about everyone I knew was playing it. This game is the epitome of freeware games-when you've got a few minutes and you don't want to bother loading up a serious game, just hop on over to Crimsonland and splat a few hundred (or thousand) bugs.
In case you haven't gotten this game yet, it might be a bit hard to get a copy of it since the main site is currently down. But if you're reading this page then you probably already have it anyway!
This game is perfectly mindless... you grab big guns and shoot tons of bugs, who keep coming back, but thank goodness your ammo recharges like in Liero, and you have powerups like ice (freezes the enemies), fire shot (makes your shots do more damage and blast through dead guys), and a force field that protects you from harm. Last but not least is the bomb... it might not be the most useful powerup, but it looks the coolest when you set it off!
My favorite gun is still the plasma minigun, and my second favorite is the sawed-off shotgun. If you guys are reading this and you have the latest version of Crimsonland, we have to swap high score files, if I can figure out how to combine them.