Very few games blow me away. It either has to be some kind of incredible scale that I wasn't expecting; or some kind of alien feeling to the game that I've never felt before. To illustrate with examples:
Final Fantasy VII (when you finally exit Midgar and realise there's a whole bloody world out there)
Jak & Daxter (moving seamlessly between areas without loading screens)
Jumping Flash! (in the second world where you see far off objects in the distance and realise you can leap your way towards them)
Pikmin (playing the first level which feels kind of familar yet completely otherworldy at the same time)
SSX 3 (when I realised I could race down the whole mountain in one 40-minute-long trip if I wanted)
The most recent example I can think of is Ratchet & Clank: Tools of Destruction when you're in Metropolis. Although I'd seen the level in Up Your Arsenal, exploring it in HD for the first time with the full power of the PS3 rendering all sorts of vehicles flying through the air; platforms crumbling; enemies everywhere; explosions etc. was just mind blowing. Combined with the Pixar-esque graphics, I just couldn't believe how fantastic it looked.
