Having recently discovered TIG (The Independent Game) Source site, i’ve stumbled accross a few excellent examples, both single and multiplayer, that you should check out.
Gravity Hook
The first and easily most addictive game I got stuck playing was Gravity Hook, by Adam Saltsman and Danny Baranowsky, a flash game simply based on single click frenzied gameplay.
Effectively you take control of a circular pod which has to hook onto mines in order to climb a column based level. Fine right? wrong, the problem being as soon as you attach yourself to a mine and begin to climb, the mine is armed. Stay attached too long and the mine explodes, as do you.
If it sounds simple then that’s because it is, and it rocks, I love the simplicity, and the 16bit pixel style that evokes snes era metroid esque (albeit simplified) gameplay. Plus! its flash based, so you can play it in browser. Click here to play.
Karoshi 2.0 / Karoshi Factory
Another fine example of addictiveness, this time not in a frenzied vein, but in the form of puzzle solving ingenuity. Far too difficult in places for my meagre brainpowers, but excellent for the seasoned gamer – or to try and crack with mates, Karoshi goes against the vein of all platformers.
The job is not to survive its levels, but to.. well actually that sentence works fine – the job is literally not to survive each level. To progress through the game you must figure out how to kill yourself in each level, from getting things to fall on you, to getting bullets to fly back at you, to good old fashioned impalation (its a word i’ve made up to pluralise ‘being impaled’ it’ll do) Karoshi 2.0 / Factory seems to be able to find no end of baffling puzzles to defy the user’s expectations – including at one point in Karoshi 2, the involvement of your CD drive! you’ll know it when you hit it, props to Hendo for working that one out! Sadly its a windows only affair, but what did you expect mac users, its a game! (boohoo). Get involved here! for Karoshi 2, or for Karoshi Factory, click here
Teeworld (formerly Teewars)
Another fine example of cutdown gameplay here, this time the shooter genre being the source of inspiration.
Taking command of a small Kirby-esque character, you play online in a frenzy blast of fun, dashing around in 2D, collecting weapons and destroying other players as fast as you can. Paying homage to more conventional online shooters such as the Quake and Unreal franchises, the game features weapons that players of those FPS games will certainly recognise.
Also, this is cross platform, so mac users can get involved too, so why not download and get involved right now?

World Of Goo
Ok you got me, this is more of an honorable mention as its another example (one of too few sadly) of Indie games crossing over to the mainstream. Other examples in recent memory such as Darwinia and Alien Hominid made the leap succesfully, and now World of Goo has finally made the leap from being a student project, to a commercial product, and its a great simple game, all about building.. with goo! its a fairly straightforward and highly addictive physics based affair, that you can grab a demo of right here
Aether
Aether is pretty different to the others i’ve listed here, in that there isn’t any obvious goal I could name. At least not one i’ve spotted so far.. Not to say thats a bad thing! this is one of those fantastic exploratory games you can simply get lost in. You play a little boy riding a monster that can climb the clouds into the atmosphere and head to other planets.. discover new worlds.. its weird but strangely captivating. I’m rambling but see for yourself here