I just played through Portal 1 and 2 in a sleepless weekend. I don't recall the last time this happened, and it made me wish for HL3 all over again. To you game

I just played through Portal 1 and 2 in a sleepless weekend. I don't recall the last time this happened, and it made me wish for HL3 all over again. To you gamers out there: Is there any other experience like it that is playable on my gaming-crippled two-year-old Macbook Air?