If you've taken a look at the new issue of MagPi (http://www.themagpi.com/
), you probably saw the list of tested games. These appear to have all been looked at fairly briefly, but I thought it would be good to share experience with our own tests to both recommend games on basis of appeal and denote which games really work and which ones aren't worth the effort.
I'll make a short list here; I'm running Debian Squeeze with updated firmware, 192 mb/64 mb cpu/gpu split.
atris: kind of cool, kind of annoying. it's a tetris clone fundamentally, but it changes it up some by having some weird bi-colored block deal that bears some gameplay significance (I didn't completely figure it out) and also having flames in the background. it boots into a fullscreen window, which is unnecessary, and it plays well but I think I prefer regular simple tetris. Also I couldn't figure out how to quit during the game (in retrospect I think it may have been 'Q') so I ended up killing myself to escape. also, the menu entry didn't work for me, so I had to locate it in /usr/games/atris.
ace-of-penguins: no problems. It's a fairly simple game set, mostly card games, but includes a minesweeper game, which is why I got it (the field is set and you can't resize; it's really simple). It all plays fine but it's not the most entertaining. A less exciting alternative to the gnome-games package which isn't really going to work here, I think.
blobwars: totally hilarious, also a pretty solid platformer. I stopped playing because I couldn't figure out how to progress in the first level but I'm sure someone else will know how. the main issue is occasional lag, but it's not unbearable to the point you necessarily want to stop playing. it's fairly decent. this menu entry didn't work either, so I had to locate it in /usr/games/blobwars.
frozen-bubble: another one whose menu entry doesn't work. /usr/games/frozen-bubble. Anyway it lags pretty badly at first; once you change the graphics settings to lower, it runs a little better, but still isn't optimal. still, much better. anyway if you haven't played this, it's the predecessor to that bubble safari game on facebook, which is actually awesome, partly because it combines the original concept with NBA Jam. However, no NBA Jam here. it would be fun if it didn't lag while you were shooting the bubbles. tolerable, but I got annoyed pretty quickly. still worth trying.
geki3: solid space shooter, no lag that I could notice. fairly simple and repetitive, and the music is a really short loop that can send your head in for a spin. you might want to turn it off. It's cool for awhile though. I didn't try geki2 but I assume it's similar. This one doesn't even have a menu entry, but you can locate it at /usr/games/geki3.
lbreakout2: solid breakout game-- works if you don't have other memory intensive processes. good game.
micropolis: I confess as soon as I booted it, the screen was static and too big for my desktop, and I thought the colors and shapes looked annoying, I quit and removed the installation. but it could be fun. I think it's supposed to be the open source release of sim city 2000 or something?
pacman: not the original, a bit jankier than the original, controls feel less precise, but overall solid remake. runs fine. no menu item; /usr/games/pacman.
petris: it runs in the terminal, but sorry, WAY better than atris. it's simple and it's better. no menu entry (obviously), no command either, so run /usr/games/petris in terminal or console.
tmw: I wanted this to work because it looked so cool, but it was way too cpu intensive. I couldn't even get it to let me register, but I doubt the game would have been enjoyable. someone else feel free to try.
that's all I have! hope this helps, and please share info on other games you've tested!