Wow, I am so impressed at the games I've never played before. They need a website for hidden gem games. I spend days trying to find something decent to play. Keep em posting!
Man, I loved Freedom Force. I still find myself humming the "Nuclear Winter" song to myself at random intervals. There are two old games that I played growing up that you can play online: the original roguelike, Rogue, and Taipan !
Aquaria : It's soundtrack is awesome , the gameplay is very nice as well . It was the first RPG that i enjoyed playing . Drawn series : I've played 2 games in this series and i have to say they are hell of 2D point n' click - hidden object - adventure games . Its music , art , atmosphere are amazing .
I'll second Aquaria. It has an amazingly interactive world with a lot of hidden depth. The game has some real meat on its bones. The moment when the main character saw the sun is one of the most memorable in my whole gaming career. I enjoyed Aquaria a great deal. The game has elements from Metroidvania, Dungeon Master and two-stick shooters rolled into one great RPG package. You can e.g. cook your own food (potions) and discover new recipes by trial and error. You can have pets. There are hidden secrets. There are boss fights. There are collectable treasures. You can ride a sea horse. One of the two Aquaria creators is Derek Yu of Spelunky fame. You can see elements of Spelunky in Aquaria and the same great game design sense at work.
I cried on the inside when i heard that there would be no Aquaria 2 because Derek and Alec no longer worked together and Marian was cancelled
If you wish, you should give Patchcon: Defend the Library a try (its free). It needs an English patch (which is free) but it is a very neat tower defense game with a Touhou twist. This is from an Extra mission.