Batman: Arkham Asylum, Donkey Kong Country 2 and Metroid Prime... Respectively my 3rd, 2nd and 1st in my top 5 games of all time. The sense of discovery and empowerment... Something I never found in other games... Cough... Zelda... Cough...
Hmm... I'd say Minecraft. Such a unique and fun feeling that you can't get back.
The original Animal Crossing. I'd love to spend hours working on Nook's Tutorial again and being so entranced by a virtual world and not have any dislike towards any animal. Also Pokemon, for nostalgia reasons.
okami amazing experience 10/10
Metal Gear Solid 2 or 3.
I've played both of those so many times, but the first time playing them was the best. MGS2 had a really well-written story, one that challenged the player's intellect while at the same time trying to confuse them as much as possible. And MGS3 had a really big emotional impact on me.
If there were ever any games I wish I could have a fresh experience with again, it's those two.
