Some demos...
Encleverment Experiment: I almost bought this when it first came out. It's a Big Brain Academy clone released a little too late to take advantage of the craze. First things first, it is significantly better in presentation and activity design than Mensa Academy or Brain Challenge, no doubt there. So if you're looking for a Big Brain Academy/Brain Training-style game, this is the one to get. It's got a really cute presentation. It's more gamey than Brain Training, so don't expect IQ measures or anything. toythatkills is #3 in the world in one of the leaderboards. Unfortunately a lot of the game is built around enjoying it in multiplayer, and so it's not the sort of game you buy years later. I don't think I'd get my money's worth, but I again think that this is a pretty good game.
The Undergarden: I played this demo when it came out and thought "cute and harmless". This time I played it and thought "cute and harmless". It's a level based puzzle game where you move a cuddly bear teletubby thing around a screen, cause grass to grow and flowers to bloom, use the flowers fruit to activate weight and anti-gravity switches, which opens corridors, which lets you move through. It's very colourful and very welcoming. In the tutorial level I didn't see anything that could injure you, so I'm guessing there aren't any enemies. It reminded me most of Soul Bubbles in that the levels were kind of tunnel-and-clearing setups and you float around in any direction, although the mechanics are different. I bought this because it was 240 msp and might get delisted soon. The game has co-op but I can't see how that could possibly benefit it--this is definitely intended to be a single player game. Cute and harmless.
Rez HD: I only played Rez once, a long time ago, on PS2, and I didn't have any strong memories of it. The demo was surprisingly pleasant. It's basically a rail shooter where you can't dodge, only attack. Your attacks fire to the beat of the electronic music in the background, so there's a slight delay. It uses the aim-lock-and-fire method of controls (which exist in some form in many rail shooters, but reminded me most obviously of Child of Eden). You fly through cyber-mainframe-wireframe corridors. After killing so many enemies you get experience that adds towards you levelling up. You start at level 1 and can level up to level 3. When you get hit, you lose a level. When you're level 0 and get hit, you die. It apparently has an adaptive difficulty system, which I guess means I'm a poor player because I found it pretty easy. My key question is this--what separates an average Rez player from a good one? I killed everything, I tried to get pretty big chains of enemies and only actually fired when I absolutely had to. I didn't get hit by anything until the boss. How would I replay that level and do better or worse? The presentation is great, with lots of code-server-gibberish being fired off, clean and visually easy to distinguish graphics, and great music which interacts with the gameplay. I found Child of Eden more engaging, but I'd definitely be willing to buy Rez.
Risk Factions: I played this one before and came away from it saying "This is an enormous filesize so you can add a low-quality flash animation story to Risk."... and that's basically what I came away with this time as well. You know what the fundamental problem with electronic versions of board games is? When they use animations, visual effects, menus, prompts, and text to slow down playing the game. Electronic versions of board games should be FASTER than the real thing, not slower. They should at least have the option anyway. The story is stupid and basically internet meme level. I didn't really like the added stuff for the campaign (of which I think I was able to play 1/5th of as a tutorial). Also Risk isn't a particularly good board game, so there's that too.