Torchlight is a dungeon crawler in the vein of diablo. Lots of equipment dropping, items to get, etc, as opposed to the more platformer-style of Trine.
Very, very different games that happen to be set in the same fantasy genre.
I enjoyed both games, but if you like Diablo, you'll love Torchlight. Torchlight 2 is coming soon too, I believe.
The game has some okay graphics and the loot system is decent. If you enjoy looting corpses for a slightly upgraded item over and over in a noxiously repetitive manner then I say go for it.
Five people in my office bough the game. I played it on very hard and beat it. I was the only person to reach the end despite everyone else playing on normal difficulty.
I beat the game out of spite. I never felt so angry at a game before but my sheer hatred of it drove me to finish.
I guarantee most positive reviews come from people who did not finish the game. It's just not fun after the first 10, 20, 30, 40, infinite floors in the same dungeon.
