Your character is loaded with so much loot, a great deal of which is unidentifiable initially, that you're forced to leave your dungeon crawling to identify and sell the dozens of axes, maces, and wands you find. I'd routinely sell my goods and then spend the next ten minutes going to the various townspeople that independently performed one function towards augmenting my armory with gems. The gems grant you bonuses like protection against fire, additional armor, and faster health regeneration. By combining their fragments, the gems become more powerful and can be slotted into weapons or armor. You can destroy equipment to use the gems for later use or destroy the gems to retrieve the equipment (thanks two to orcish smithies in town). You can also augment your armor by going to the enchanter and spending money to enchant or add gem slots to your equipment. For those who like to micromanage their character, the gem, enchantment, and leveling systems provide plenty of options to upgrade your character. For those who tire of spending a significant part of your adventure leaving the battlefield to go shopping, the system gets tedious.
The soundtrack and voice acting are pretty forgettable, as is the tired plot of some kind of evil that lurks beneath the town of Torchlight. The fact that the dungeons are varied is explained by the idea that it's a "layer cake" of past civilizations and the deeper you go, the further back in time you go. The characters in the story simply exist in the hub to give you quests that usually involve collecting an artifact or killing a beast on a particular level. Aside from obtaining more loot, fame, and experience, there's really no reason to undergo any of the side quests. They don't expand the world or story and often require you to backtrack through dungeons you've already fought through.
Like Diablo, the view is isometric and uses a point and click interface. You'll want to use your hot keys to assign spells, potions, and other abilities during gameplay, as these come in handy during intense combat. As an Alchemist, I assigned a lightning spell in one key, a fireball in another, and finally a focused beam in the right-mouse button--the combination could take out pretty much anything, regardless of its elemental strengths and weaknesses.
On my Core i7 iMac, Torchlight looks fine. This isn't a game you play for the graphics or for the realism. It's a dungeon crawler and the lightning, fire, and gore effects are all pretty satisfying, on the whole better than Fate and the Diablo series and comparable to World of Warcraft. I didn't experience any frame rate issues, though the constant load-screens when jumping between town and the dungeons can be a drag.