I've got to play devil's advocate a bit here - personally, I don't think games are even close to creating the same emotional impact that a really great movie can. Some games have come close, and I'll mention some of my favourites in a minute, but that's a tiny, tiny minority compared to the vast number of films that can create a huge emotional impact.
I've yet to see a game that really challenges the impact and emotions stirred at the end of 'Once upon a Time in the West' or at finding the graveyard in The Good, the Bad and the Ugly. A game that made me almost cry the same way that the suicide scene in MASH did, or the haunting telephone call in Taxi Driver. I can't recall any game really feeling as exciting as when that sword comes out at the end of Kill Bill. I don't think there's been a game that creates the same unending, hopeless sense of tension that Army of Shadows or Key Largo creates. Nothing in GTA really makes me feel the same sense of amazement watching the main characters enter the bar on a date in Goodfellas... I could go on, and I really could go on for 1,000, even 10,000 movies, but you get the idea.
But my main point is this - who fucking cares? The problem with compared a movie to a game is that the two aren't doing the same thing. There are similarities but they aren't the same. But criticising games for not being the same as movies it's just an excuse for gamers to tie themselves into knots defending the hobby they enjoy.
A movie has a huge amount of interest in creating an emotional reaction - because that's all it can really do. Whether it's excitment in an action scene, blubbering during a romance or tension in a Hitchcock thriller - there's nothing else to do. A movie can't suddenly let you try to save the life of someone during an operation - it's got to construct a world and a perspective that is designed to twist emotions.
Now a game can still do this, but it's much harder. Perspectives change, angles, montages, pacing and rhythm are harder to maintain. The timing is harder - people drop in and out games rather than watching them in one go. To be fair - games do have less emotional impact - but when they do, it's been fucking earnt.
But the biggest problem is that without pointing out everything else games do - the challenge, the pure activity of playing the game, the sense of fun and freedom - then it's just games trying to justify themselves by the standards of a different medium. It's a deadend arguement designed to let movie snobs win.
However, saying all that, I really did feel overwhelmed by Silent Hill 2 - especially as it became clear how the plot was playing out and the revelation about the events in the game in BioShock was amazing! - Easily up there with the Usual Suspects for me.
So, I think games can have an emotional impact - but it shouldn't be expected or a problem when it isn't there, just part of an overall experience much broader and much more fulfilling in the long run than most films.
Although I would argue that games do need to grow up a bit (if they want to create a real emotional impact) - the holocaust scenes in Band of Brothers are so moving and when they had to take the food from starving, dying, survivours and lock them back into the camp... A game could do the same and could have the same, or even more impact, but that's not going to happen in the next CoD is it? Instead you'll just be blowing away 1,000s of Nazis and Japs again.
So, I reckon it's fine that games do different things than movies - I just think they could also maybe grow up a bit and try a bit harder to have more of an emotional impact, but it's by no means necessary, at least in my eyes.