This is the third time I've played this game today, it's so catchy. Can't wait for Zen mode, imploding the universe three times in one hour makes me feel like a bad person.
Great game. As other comments show, the game was fairly easy, so much so that I don't believe that the knight, whom I used as a tank, ever dropped below half health. One small change you could/should make is adding a LOS/range nerf to the healing spells, so that the healer has to keep up with your party (and therefore in moderately more danger). Some more variation between the classes would be nice too, so that they fit their respective roles better. 5/5, and I'll look forward to the second installment.
Zen mode is not far off! Just needs a bit of tuning and a new level generator thingie. =) Expect it later today or maaaybe tomorrow.