I think the problem is that computer games are going though a stage of 'it's just like being in a movie!', when what they should be doing is trying to make into just like being in a computer game.
Computers have incredible powers, and yet I haven't seen anything commercially to challenge ideas such as Zero-Gravity pool or The Incredible Machine, which were released in the 80's originally. Nowadays, every FPS wants to be like an action movie, every RTS wants to be Lord of the Rings. Too much time trying to make computer games realistic, not enough realising the sheer joy of a computer is that they don't have to be. I can understand that RTS can only 'look' a certain way as can FPS, but the actual elements of gameplay are all mirroring each other, a new innovation these days seems to be involved with how the game looks/interacts not with how the game plays.
Everyone is calling 'Portal' an innovative idea, and it is for this day and age, but, compare the gameplay to the 80's and you'll see they've learned from the past, it's a simplistic idea that uses a computer's ability to do the 'impossible'.