A wonderful, simple, and possibly addicting game
Torchlight is a new entry into the Diablo-style hack'n'slash genre of games. While it may seem derivitave, it bears mentioning that some of the team behind this game also worked on the actual Diablo games, and one of them is the guy behind Fate.
Not much here to start with--three class archetypes to choose from (melee, ranged, or mage). Each character has their own brief backstory. I played as the melee class; my wife is playing as the ranged class, which involves both bows and guns. More customization comes in upgrading your character--each one has three different skill tracks to upgrade. Personally, though, I would argue that this game's REAL customization potential is in the loot. This game is loot-heavy. Some items have slots that you can upgrade with runes. In town, there is an enchanter (which as another reviewer mentioned is the real money-sink in this game), and also an NPC who can combine duplicate runes into better ones. Some loot is in "sets" that provide bonuses the more pieces you have equipped, though I've found mish-mashing stuff I find to be the best way to go.
Colorful. Vivid. Confusing. The enemies will swarm you (load up on AoE skills!) and it can often be hard to tell exactly what's going on, but a few clicks of said AoE skill can usually clear them out fairly easily. For those playing on non-gaming netbooks, there is a "Netbook" option under settings that makes it much more playable (we tried this with the demo on my wife's computer before I bought it on mine, and it seems to work well).
The pet is an interesting mechanic. The fish you can find throughout the game (via, well, an easy-to-grasp fishing mini-game) can be fed to your pet for temporary transformations or stat boosts. These will greatly increase your pets HP, and bestow temporary abilities depending upon the type of fish consumed. They generally last for 120 seconds, though there are variations. Perhaps the most useful aspect is the ability of the pet to run to town and sell stuff in its inventory, which is just as big as yours. Due to the decently high drop rate of potions, the only thing that really might make you go back to town in the middle of a dungeon is using up identify scrolls. You CAN learn an ID spell, though it takes up one of your 4 spell slots.
The real measure of a game. The gameplay here is not deep, thoughtful, or difficult. The enemies--even most bosses--are pretty easy to kill. This is not a criticism per se--I downloaded the demo before purchasing this game, so I knew exactly what to expect. When it comes to games, I'll play a certain game for weeks on end, tire of it for a while, then play something else in a different genre. This is a simple game, but the dungeons go on for a VERY long time. I played through and "beat" the story (which ends on about level 35-40, I can't recall exactly). I'm playing other things now, but I still bring this game up when I want some mindless loot-grinding. It's a good game to kill some time while waiting for my wife to get ready if we're going out (she feels the same away about when I'm getting ready!). Even though the main quest is completed, there are still NPCs outside of a secondary, more difficult dungeon (the Shadow Vault) that are giving me quests.
Bug, Glitches, Issues:
A relatively common one I've found is enemies and the loot they drop getting stuck in walls or behind objects that appear traversable but are not. To my knowledge, no patch has been released addressing this, though if I am mistaken, please let me know. Occasionally your pet will get stuck and trail behind you, though this is easily fixed by doubling back and running in a little circle usually (though it is rather annoying). The save mechanic uses (in the Steam version, and when connected) the Steam Cloud. HOWEVER: The game does NOT require an internet connection to play, or save. I've found the best thing to do when done a session is open a town portal, and go into town. The game saves, will reload you into town the next time you open it, and your portal back into the dungeon will remain there. I've had several game-killing crashes (which on reloading means I start at the beginning of a dungeon floor), though this is not prevalent enough to make the game unplayable.
All in all, for a game that had a development-to-market cycle of 11 months, with an engine built from the ground up in this time, Torchlight is still surprisingly well-done. The cost is a definite positive point of this game. This game can definitely cause the "just one more turn!" (or dungeon level, or boss, in this case) mentality, but it is also easy to pick up and play for an hour without having to invest much thought or effort in it. If you liked Diablo, Fate, or just the dungeon crawling, loot-grinding genre in general, this game is a can't-miss.