Tales of Maj'Eyal

ToME is a fantastic roguelike with classes that really do play wildly different from each other. Many have their own system of resources and spending, as well as a myriad of abilities that do more than simply "subtract X HP from a monster X squares away from you" and an absurd amount of skill/weapon customization. It's an open world: wander off in any direction and you'll find something to do and lots of hidden bits of lore. It has the complexity of ASCII games, but with a UI that's much easier to pick up. Permadeath and "rogue lite" modes are both available. Elite enemies are modified from a long list of skills and buffs which sometimes randomly synergize to make monster that's effectively way above the area's level range. It sucks to be walking around the forest doing fine, only to have your character one-shotted by a lightning strike off-screen, but instances of this are pretty uncommon. Overall I found that the difficulty curves fairly well as long as you pay attention and know when to back off. Definitely recommended for any dungeon crawling enthusiast.

graphics are a bit wonky but the game is super fun, been playing this off and on for years

Very challenging

see above be prepared to die many many time have fun

A true roguelike with lots of text style lore, tons of differnt classes & races. The gear is very cool tool, and man can the game get hectic VERY quick. RECCOMEND for thoes of discerning tastes.