The most surprising thing is that the story and especially the dialogue are excellent, not something you normally look for in a tower defence game. The gameplay is also very good. I was slightly put off by the fake "difficulty levels" (except for "casual", they're difficulty levels of the diablo-style, i.e. more like new-game-pluses, which is very odd, since the game features an actual new-game-plus as well). It's a good blend of rpg and tower-defence; the combination actually works.
I really can't engage with a game in which there're no characters at all (not even implied ones like in a god-sim). One might argue that perhaps I shouldn't have bought it; it was part of a package offer and my fifth choice and I thought I might as well try it. I didn't notice anything obviously wrong with it (in my about 10 minutes of play), though, if you like the idea of the gameplay, but I just couldn't get into it.
Well, there's nothing glaringly wrong with it, I suppose. It's a heroes-of-might-and-magic/ age-of-wonders - like game (a little more like the latter, I think). The graphics, while basic, actually look pretty good, though be aware that there is no animation whatsoever, only static tiles. But playing it feels rather a lot like a chore. It's full of more-or-less random events, which often repeat themselves since there aren't a whole lot of them. It dispenses with free movement in favour of having heroes and their armies occupy a province and slightly-abstractly "explore" it by clicking the appropriate button. Although there are a lot of units, you only really get one faction to play, so far as I can see (there are apparently ways to access to units of other races, but your stronghold is always a human keep). And the campaign story is horrible (par for the course for this kind of game, but I think this one is worse than most). Suffers a bit from problems that Age of Wonders has, as well; heroes are a bit overpowered, and there's really no reason to use weaker units since you're limited to a fairly small number of units in an army (and you can't combine adjacent armies like in AoW either). So in summary, not terrible, but didn't sustain my interest beyond a few hours, and I doubt I'll go back to it.
The translation into English is very poor, which completely destroys the atmosphere the game is trying to create. This would be unfortunate in any game, but in an RPG like this that is depending quite strongly on atmosphere it's almost enough to kill the game by itself. Also, the combat is tedious and clunky, and the first quest you get given is of the "kill 10 bats" variety, only worse, since the game doesn't tell you how many you need to kill. There appears to be no way to interact meaningfully with any NPC until you've completed this nonsensical and tedious quest. I gave up after about half an hour.
I really don't like D&D rulesets applied to real-time combat. It doesn't work here at all. Worse, the designers don't really seem to have considered the D&D rules in designing the combat. Gameplay is full of hordes of respawning enemies. This makes playing a spellcaster very frustrating, since you run out of spells in no time. The camera angle is also bad; you frequently get attacked by enemies you can't see no matter how you angle it. The graphics are dull and unispiring; mostly just a mess of grey. The "wheel" interface is confusing and awkward to use. And the plot is the most dull, tedious, derivative and badly-acted thing I've seen in a while. I just can't see what anyone sees in this game; it doesn't seem to have any good features at all. If you want D&D combat in a computer game, even the buggy Temple of Elemental Evil is far better.
The storyline and characters are excellent (for a crpg, obviously- we're still not really approaching novel quality). The dialogue writing/translation is a bit dubious at times, but even the voice-acting is quite good. My problem with it is the gameplay. I don't like the combat system at all (it is undeniably a bit weird- you won't find anything like it in any other game), and character development is very limited- you're basically constrained to two options: swordplay or signs. You can't even (effectively) use any weapon other than a sword.
Well it's quite a competent, reasonably fun game. Far from perfect, though. My two main complaints would be a lack of variety in the level aesthetics (basically, there's an outdoor aesthetic, a castle, and cave and that's about it), and a rather frustrating difficulty in places. The game definitely seems to have been designed with experienced platformer players in mind; there really isn't an easy mode. The main game mode (adventure) gets quite difficult 4-5 levels in, with checkpoints becoming quite scarce, and all the other game modes are insanely hard. I gave up about half-way through, but I think I just about got my money's worth out of it. Oh, and the engine isn't very well optimised; if you have an old computer you may find it difficult to play. I managed to get it to run smoothly by turning all the graphics settings to minimum (it still looked pretty good). Music is quite nice; it does look pretty, and it's certainly entertaining for a while. The gameplay does rather depend upon learning how to get past a section and then executing the right moves accurately. There are multiple ways to get past a lot of them, though.
Well it's no Diablo, I'm afraid. I have difficulty explaining exactly why, though. There's relatively little obviously wrong with Torchlight; the controls are intuitive, the gamplay reasonable, the voice-acting bearable (which is itself far from a garuantee in computer games in general). It's alright for a little while, but I couldn't muster the interest to finish it. It fails to create an immersive atmosphere as well as Diablo. Everything's a little too cutesey and the characters are largely 0 or 1-dimensional. The skilltrees seem somehow pointless; it doesn't seem to matter much how you invest your skillpoints, especially since the game is so easy on Normal difficulty (I strongly suggest starting on "Very Hard" actually, if you have any sort of experience with this kind of game). There also almost no penalty for dying, at any level, which reinforces a general sense of pointlessness. The game is also more-or-less totally linear, with each level of the dungeon following the previous one, and the aesthetic only changing every few levels. One can technically go on "side quests", accessed via teleporting maps from the main village, but these feel even more pointless than the main plot, since they have no objective beyond "find some treasure". All in all, probably just about worth the money if you're desparate for this kind of diablo-esque game, but I wouldn't get it with terrible high expectations.
Closest thing to a flawless game I've seen. About the only complaint I could make is that the environments are a little samey (something the sequel, from memory, manages to avoid). Otherwise an extraordinarily good game, albeit one that does nothing really new or innovative, just gets everything absolutely right.
