Here's my impressions on the games I've downloaded so far:
Tic Tac Toe Free: It's Tic Tac Toe, what do you expect?
Paper Toss: A decent time-waster.
Labyrinth 3D: Reminds me why I hate the real-life version of those things. Also, what's with the background music?
Unblock Me Free: Wish I could move other blocks besides the ones I'm supposed to...
Chase The Dot: OK for a few seconds.
Pop Lite: Relaxing. How does it compare to the WiiWare version?
Bloons Lite: kinda tricky.
de Blob Lite: It's weird, because it shares a lot of the same elements with the Wii game, except it's 2D. The lower power of the iPod Touch means the game loses a lot of the style that the Wii version had. Still, it makes me wish the Wii version had had an option for tilt-controls.
Spore Origins Lite: OK; the graphics are good. I couldn't quite tell how the customization affected the gameplay...
Rolando Lite: Pretty cool and stylish. Uses the iPod Touch features well.
Toki Tori Lite: Puzzling. Made me think. I liked how each time I had to restart, I had learned something to do better the next time. How does it compare to the WiiWare version?
Metal Gear Solid Touch Lite: Didn't really do much for me since I'm not that familiar with the Metal Gear Solid universe.
Chess Free: On easy, the AI lost to Blitzkrieg. Wow.
Dots Free: The AI is pretty stupid on easy here, too. I drew lines in the wrong places a few times.
Checkers Free: OK. I don't play checkers that much, so I can't really comment on the AI.
Sudoku Free: Took me a bit to figure out the interface, but I once I got it, Easy was easy.
Pac-Man Lite: None of the control options really fit this game that well. They should have made a new Pac-Man from the ground up that's actually built around the iPod Touch's control scheme rather than porting the original.
Solitaire Free: Why no dragging and dropping of cards?
Blackjack Free: I don't really play Blackjack much, so I didn't get into it.
Hangman: OK version of hangman. I like that it gives you a dictionary definition after. I clicked the wrong letter a few times.
iBowl: The controls feel kind of different from Wii Sports. It's hard to adapt to.
Target Practice: 10-second time waster.
Free Minesweeper: It works better than I expected.
Topple: I preferred the Flash version. Rotating pieces is kind of tricky.
Assassin's Creed: Altair's Chronicles Lite: I could kind of tell it used to be a DS game in some parts. All the geometry being at right angles made me wish for a d-pad instead of a simulated analog stick so I wouldn't slip off as easily. The graphics look better than what can be done on the DS, though. Overall, which one is better?
Castle Magic Lite: Cute and happy. I like Gameloft's engine. The platforming is good, too.
Hero of Sparta Lite: OK. On one hand, the combat seems to be a little shallower than in Assasin's Creed, but on the other hand, the QTEs feel like a better use of the touch screen. I like the setting better than in Assassin's Creed, too.
Zenonia Lite: The interface sucks. What's with all the scroll bars and buttons that don't work when touched? You're already using the touchscreen to simulate the d-pad and buttons, why can't I touch the part of the screen that makes sense instead? Either actually use the touchscreen, or put your game on a platform that has a d-pad and buttons. This is how I feel about games that use the touchscreen to simulate a d-pad/analog stick and buttons in general, but Zenonia is the worst offender I've come across so far. The actual RPG parts are okay though.
Wolfenstein 3D Lite: I never played the original, so I'm wondering, did the graphics get an upgrade? They look cleaner than what I would expect for the era. In general, the game seemed to feel more like a 3D maze with the occasional enemy rather than an actual FPS. Granted, I was playing on easy, but still. I wish the DS would get a version so that the map could be displayed at the same time as the gameplay so I wouldn't have to be stopping to check it all the time.
Heavy Mach Lite: Kinda fun. Took me a bit to figure out how to jump. I wish it had background music to break the monotony of the gunfire though.
Brick Breaker 3D Free: The controls are hard to choose between. If I use the buttons on the side, it's not as precise, but if I touch the paddle directly, I can't see it. That's something I kind of dislike about the iPod Touch in general: having to touch with a finger instead of a stylus means a lot of the screen is often covered up, making it harder to see and less precise.
Galaxy on Fire Lite: Kind of reminds me of EV Nova, except more linear and with 3D combat. I switched to accelerometer controls. I'm amazed by the 100-point difficulty slider. I turned it down a little (to 39).
Isotope Lite: The accelerometer controls worked well the first time I played it, but since the latest update, they don't seem to work for me anymore.
iFighter Lite: Hard.
Nano Fighter Lite: Why doesn't the background move when I move? I think I kind of prefer Isotope.
Dropship Lite: Is there a way to invert the flight controls? Also, what am I supposed to do with the thing in the first level once I pick it up?
Zenbound Lite: Relaxing and interesting.
Zentomino Lite: It felt kind of weird playing this after my brother had just been playing with real life Tangrams.
Totomi Lite: I never went back to this after the tutorial.
Archibald's Adventures Lite: Fun and puzzling.
Tiki Towers Lite: I hadn't expected the building and the letting the monkeys loose to be separate. How does this compare to the WiiWare version?
Eliss Lite: I didn't get this at all the first time I played it, but after coming back to it, it's kind of cool.
Sway Lite: Pretty hard. It took me so long to beat the first level.
Dizzy Bee Free: OMG 360º screen rotation! I love it!
Defend Your Castle Lite: Easier than what I played of the multiplayer mode in the WiiWare version at a friend's house.
So that's what I've played so far. Also downloaded some non-game apps, which are also cool. Haven't paid any money for anything yet, which is nice. Should I pay the $9.95 for the update to system 3.0? In general for games, I prefer the accelerometer to the touchscreen. I haven't seen any games yet that use the touchscreen as well as Zelda: Phantom Hourglass uses the DS's touchscreen. Still, the iPod Touch in general makes me wonder why Nintendo didn't put an accelerometer or a GPS in the DSi or make its touchscreen multi-touch. I hope these features will make it into the next DS.
(8 players online, voice chat, Terminator-like controls). It could easily be a hit as it would be the first shooter with a real competetive online part.
