Yes, yes, yes! Cosmo's Cosmic Adventure was awesome. I wound up getting all three parts and I played them for the longest time. Then my parents made me uninstall it, then they got rid of the Windows 3.1 and 'lent' my games to friends of the family, who never returned them and I can't even remember who we lent them too. Just like our copy of King's Quest VI, which I still love.
I just played through Another World for the first time last month. I remember trying it out at a friend's place years ago. Man, that's a challenging game, but so cool (It surprises me that no one seems to have done a ReMix of the music from that game; I think it has a lot of potential to make some really cool shit). Still, the original Prince of Persia still takes the cake for hard games I can''t seem to get enough of; I STILL haven't beaten it.
I played a lot of point-and-click adventure games back in the day, and I'm sad that the genre isn't so popular anymore. I mostly played Sierra games, especially the King's Quest series, which I blame for my obsessive save-pointing with any other game and for my habit of carrying tons of useless crap in my bags). I also loved The Incredible Machine, which I'm sure has been mentioned.