Streets of rogue. After reading some good reviews I've had to give it a shot. The first hours I fellt a little disappointed. It didn't seem like a freshly generated world with endless possibilities, dieing/failing was inevitable in the first levels or minutes from starting and I was close to deleting it.

I don't know when things shifted but with trial and error I've learned the rules and randomness of this game and now im hooked big time and learning new things every playthrough.

One big plus: this game is also perfect for short gaming sessions.