Portal was incredibly short, but it was still worth it BECAUSE it was sooooo replayable.
Games that have high replay value are considered (by me at least) to be a longer game...
~Sol
um... i played it once, and then i waited for half a year before i played it again, so that i would forget some of the puzzles. If there are secrets n stuff i haven't found them yet. But i still think it was worth it.