Decent
This game is pretty decent, and kept me entertained long enough. The progression of items and enemies is pretty good.
Here are the problems:
1. Class balance - the Wizard is much better than the Fighter and Thief (whether Fighter or Thief is better depends on the spells you get).
2. It's all about luck - beating the game is mainly about finding the right spells in the beginning. A wizard with 2x fireball has enough firepower to destroy almost anything (especially if you have 2x spells that disable, such as fear, freeze, and charm, and 1x spell for fleeing, such as teleport). With 2x fireball, you can basically just turtle and recharge. For fighters, the heal spell is very useful, and can make a big difference. If you have no fireballs, the game will eventually progress to a point where you can't continue once you run out of healing potions, because engaging in melee will risk losing life.
3. The ending sucks. There are no boss battles.