Icy Tower is a fast paced and addicting game where you must continually be going higher and higher up through the tower in order not to die. You try and set highscores by getting as high as you can up the tower, you can also increase your score by doing jumping combos. In the game you can play multiple characters and also watch your replays.
One of the best finds on the web is Soldat. Not only is it crazy, multiplayer, shoot 'em up fun, but it's FREE! Choose your arsenal of weapons at the start of each round and then proceed to either play capture the flag with a team at your back, or fight a crazy free-for-all deathmatch, or fight alongside your friends against hordes of zombies!
Gang Garrison is multiplayer platformer "demake" of Valve's Team Fortress 2. It features all nine classes and many TF2 inspired maps. It is fast-paced, team-based, craziness that will have you playing hour after hour. Admittedly the graphics aren't amazing, but the speed and fun of the game make up for it. Everyone should try this delightful little game out.
Little Fighter 2 is an action beat 'em up in which you use a combo of keys to unleash devastating attacks; this game will have you playing for ages. The graphics are 2d and rather pixelly but they fit the game well. The game has several modes including a stage mode which you play as a team against a lot of weak enemies, and a versus mode in which you can either play free-for-all or with teams verse bots, or human players hotseat, or against human players LAN. This is a free game that everyone should take advantage of!
Liero is an old classic that me and my friends would play for hours growing up. In Liero two worms fight each other to the death for frags. You get a choice of five weapons out of forty. Most of the terrain (besides rocks) can be dug out or blown up. In addition to his weapons each worm has a ninja rope which can be used to get to higher ground or to soar through the map faster. If you are a fan of old retro games then this is for you!
A rather insane, 3D, abstract, scrolling, shoot 'em up game. The goal of the game is to progress through levels and to not run out of time, you lose time when you die, and gain time when you destroy small "bosses" and when you pass a level. A highly addicting game. I swear if you play long enough you will begin to see through the spinning track and shooting graphics!
Treasure Treasure is a team-work, puzzle game. You play as Trixie and Troy who must explore a castle together to find the 20 treasure chests hidden throughout. This game is best played cooperatively but it is also possible to play it by yourself by alternating between the two characters, but where is the fun in that?!
Friendly-Strike 3 is a fast paced, 2d, multiplayer, shoot 'em up fest! This game leads to some fun times either playing with up to 4 people on one computer, or playing online vs others, or playing against AI. In this game you play by rounds, only getting one life in each round. You get more money based on how many people you kill, and whether or not you are the last man standing. The more money you have, the better weapons you are able to buy. The graphics are nothing exceptional but they work for this highly entertaining game!
FLaiL is a puzzle-type game along the lines of N. If you enjoyed N i strongly recommend you try this game out. In each of 80 stages the goal is to get to the beam of light this requires exact timing and calculation. FLaiL will require perseverance to get all the way through, but if you like this type of game it will fly by. A Co-op mode also exists for those who like to play with a friend.
For all you guitar hero fans, here it is at last on computer, in the form of Frets on Fire! FoF is essentially guitar hero, you hold your keyboard like a guitar and in no time you will be playing along to the music like a pro. It's hard to get the hang of, but once mastered, you'll be rockin n rollin like elvis and all your favorite stars! A boat load of fun awaits those who try this game out.