I live for freeware games. And other stuff too... but mostly freeware games. Time for an UBER-POST!!
Action games:
Cube - An open source first-person shooter. Has network play and a built in realtime level editor.
Down - Great little game. The object is to go um... down. There are 3 different powerups. The parchute makes you go slower, the water bottle makes you fall faster, and the star makes you invisible. If you get the water bottle AND the star, you crash through platforms like mad.
Every Extend - Another strange Japanese game. In this game you have to start chain reactions to get the highscore. The levels are short and kind of simple, but to get the highscore you really have to get good.
Freedroid - Fun open source game where you are a robot and you must destroy the other robots. You can either shoot them, or take their power. Quite fun.
Frontline - Japanese again. (What'd you expect?) Your a soldier with an aresenal of 4 guns, and some grenades. The object is to get as far as you can. Watch out for helecopters.
Generally - Racing to the maX0rs. Fun little top down racing game, similar to the old arcade overhead racers. Fun fun fun.
Green Snake - Like snake, but has auto-turning, and you're stuck in a maze. More strategy, but there's a little action.
Kirubiru - Fun little game where you are a guy with a sword... who slashes buildings. Up jumps, left and right move left and right, down blocks, z slashes, and x uses special(after orange bar is full). The game is a little hard to pick up, but once you understand it, it's really fun. Keep your combo by not hitting or blocking when on the ground.
The Line Continues - Fun little action game where the whole game world takes place on a line. Has a prequel.
Little Fighter 2 - Fun fighting game. Great with multiple people playing.
Madness Interactive - A sidescrolling fighting/shooting game made in flash. Great fun. Really hard.
Mario XP - Mario game made by Japanese people. Doesn't have the greatest Mario physics, but for some reason, this game is really fun.
Neverball - Open source Monkey ball clone. Fun but challenging.
Orbital Sniper - Snipe people from orbit. Save the VIP's! Great game for a quick action fix.
Perfect Cherry Blossom - Strange Japanese game. Your a girl on a broom and have to dodge the many projectiles on the screen. Much like rRootage. The prequal is also on the site.
Pixelships - Fun little action game. Space ship side scroller with a twist. There are 160 different ships you can catch and be! Gotta catch 'em all!
Recreational Warfare (RecWar) - Fun little overhead tank deathmatch game. Fun when you have friends over, or for a warmup at LAN parties.
Sumo - An old DOS game, but still loads of fun. You get a button to control 3 leg lengths, and 5 leg angles. Fun hotseat gameplay!
UFO - Japanese game where you control a UFO and fight other UFO's. Has time trial mode too. Great fun with 2 people.
Virtual In - Japanese minature robot fighting game. Fun with 2 people.
Zone Runner 1 & 2 - Hard platform game. Levels are deviously designed and tough. Rewarding to beat though.
That's about it for now.
About N - Had this game for a long while now. Really fun. Beat the game already, and I can't wait for the online highscore tables.