Actually I found Mass Effect 2 a lot deeper if you played it on the higher difficulty. When all the enemies start getting extra shields and armor and whatnot. You start paying very close attention to the construction of multiple teams.
I enjoyed Alan Wake and also thought the gameplay much deeper and challenging on the harder levels of difficulty.
I can't stand Alpha Protocol. I rented it and just thought the protagonist was so insipid and the gameplay so basically clunky that it became a chore to muscle through. Change the game or not. Developer's need to learn that if you're going to go ahead and keep a game. It's got to be better than what your originally scoped for it.
Okay so I've decided to make a list of criteria:
1. XBOX 360 and DS. That's what I've got.
2. No PC. just in case. I want to be able to get some money back if it turns out I don't like it.
3. No JRPGs. They're becoming like plain yogurt for my video gaming tastes.
4. In and around $20 American.