Geas

I know this is by no means "modern," but I just want to say that one of my favorite RPG of all time was a game called "Dungeon Master." The graphics were cheesy at best, but the dungeons were feindishly clever and the monsters were downright scary if they snuck up behind you.

Turn around and there's a smiling mummy who screams at you. Turn the next way and there's a purple worm who eats the wizard. Huge dungeon and I have never met anyone who beat it (ridiculously difficult, but that's what made it fun).

The original Dungeon Master I managed to beat...it sure was fun and tough, though it might feel a BIT outdated nowadays , but if DM wasn't challenge enough I dare you to try Chaos Strikes Back!

If you all realy like Dungeon Master there is a reprogrammened verison vor PC compure RTC Return to Chaos it is realy funny if you have been fan of the orginal Dugeon master. And it contains both Dungeon Master and Chaos strikes back levels and Dungeon Master 2
http://ragingmole.com/RTC/