Superku: from what I understand, what you're showing is "flipping" gravity. Which is a great gameplay idea, but I don't see the "time traveling" part in it?

SirCamaris: For images etc, use www.picfront.org to upload the image, then post the link (or thumbnail link) that you get here in this thread.

@ Blink, Puzzle idea: You need to get a key that is below a very heavy object. Problem is: you can't lift the object and at the same time snatch the key. Solution: You place a "checkpoint" (enter key?) in time, then walk towards the crate and lift the heavy object. Then you wait as long as you'll need to get the key. Then you press the "go to checkpoint" key (space?) which rewinds the time to the part where (and when ) you placed the checkpoint. Now, you see your old self start walking from there to the object and lifting it. At the same time you can go to the key and get it to open the door, while your old self is lifting the object for you.
Could be expanded to pretty much anything where you need help from someone else (opening a heavy door, lifting something that you can only lift if there's more than one person, throwing and catching some object).
At some point, when the player has gotten to a higher level, we could add the ability to switch between the characters (because in the end, who cares which version of yourself saves the day). Example:
A catapult is used to throw some breakable object. You need yourself to catch it, otherwise it breaks. But you also need yourself to launch the object with the catapult. So character version 1 sets a checkpoint and then goes to stand where the catapult will fire. then he returns to the checkpoint and version 2 walks to the catapult to fire it. version 1 catches the object, player hits F2 to bring up a screen with 2 character-avatars on it, he clicks on the first one and now he plays version 1 again, who holds the object and then walks to where the object is needed.

You could even sacrifice versions of yourself ... though that might get a little too complex for a casual game .

Still, even if all this sounds complex: if setup right (and we certainly have enough coders for it) it should be no problem, but make room for many puzzle-ideas.

Sorry, long post... O.o