BlindTom said:
There's money in them Portals....
It should be: There's money in them thar Portals...
Anyway, imo, no. I'm willing to be proved wrong. But I thought that Portal was perfectly paced, absolutely brilliant, and very accessible (my non-gamer girlfriend played it from beginning to end and absolutely loved it). Plus the song was classic.
A sequel smacks of cashing in. If they can make that concept work, great, but if they mess it up, Portal will seem less awesome too (don't believe me - see the Matrix. Awesome movie, totally tainted by sequels). Call me conservative, but I'd prefer to see no sequel; leave something that needs no sequel the hell alone.
Incidentally, having an ending where all the threads are not tied up IS NOT the same as having an ending which NEEDS finishing.