Still enjoying the game, but man, it gets hard.
Finally beat the 2nd level with the Warrior last night. It was pretty close too, I was on my last sliver of health when the boss went down.
I think the Warrior is my favorite character, or at least the easiest for me to use. Both of his subweapons are useful, he has great reach and ok speed, he's strong on attack and has plenty of health. It's too bad all of his sword upgrades suck. The short sword borks his reach, the axe is too slow, the glass one makes it really hard to kill shield guys. The spin attack one is ok I guess. The shield upgrades that give him a lightweight shield are the best. You can walk around with the shield out all the time.
The Mage was my early favorite, but I find her slightly harder to play than the Warrior, partly because she's much more prone to the "aiming in the wrong direction" problem I mentioned a few times above. I like her ranged attack, I like her attack subweapon, and I like most of her upgrades (except the "salamander" one that makes her range terrible). It can be difficult to manage the energy drain even with energy recovery maxed, though. Between that and the aiming thing, I prefer the Warrior.
The Rogue is so damn hard to use. She's fun to play, but her attacks are so weak and she dies so fast that it can be a little frustrating. Also her "dash = confusion" upgrade doesn't seem to actually do anything. I do like her dash ability though, makes for much different gameplay from the other two starting heroes. Also, her weapon and armor upgrades are all pretty solid.
The Adventurer isn't bad, but feels a bit like a poor man's Warrior. He has similar strength and slightly more speed, but the shorter reach with his weapon and the lack of a shield hurt him. I still haven't really gotten the hang of using the lantern, maybe I'd like him better if I had more of a feel for that. His amulet feels like a slightly different version of the throwing axe from the Warrior. Really he's just Warrior-lite all around. I do like the bonuses to health when changing floors, though.
The Spellsword I haven't played a ton with yet, but I like him a lot so far. He feels to me like a mix between the Rogue and the Warrior, with some of the better aspects of each. He has the speed and dodging abilities of the Rogue, but the strength and some of the durability of the Warrior. Plus he gets to use all those nifty scrolls. His reach isn't very good, but his speed makes up for it. Early returns on him are positive.
Curious what the Cultist will be like. Maybe a mix between the Mage and the Rogue? Guess we'll see.