Legend of Grimrock one or two. Classic dungeon crawling mechanic with an updated look. Actually, classic dungeon crawling with updated looks AND updated everything-else.
Variable difficulty. Option of character creation (suggested for a second play through unless your intuition of party composition is naturally strong)
Pretty typical back story, setup and environment. If you loved games like might and magic, path of radiance or even old fantasy text adventures you should get this. The grind factor is just right. The puzzles are clever but not too clever. The combat is fun. It's a great love letter to the genre.