If I may briefly butt in to this debate, I think it's clear the reason you believe Portal to be overrated is because you played it a long time after it came out. As is the case with many great games, reveling in what the title has to offer in synch with the rest of the gaming community is critical to understanding what makes it great. If you'd never played Super Mario Bros. and did so today, would you consider it overrated? I'll confess that I didn't quite walk away from Portal with the same enthusiastic response as I'd heard others get, but that's because I bought it several years after it was released, on the PS3, with full knowledge of the spoiler(s). Nevertheless, I enjoyed it muchly, and anticipate the sequel.