I thought this game was challenging and fun. It makes you work out tactics for each creature since there's no save and you risk dying if you don't use the right tactic each time to get through all 16 levels. Tactics also change based on what you find. Made it to the end once, and didn't try and clear each level after about 12, just found the stairs down and kept going (lots of stealth).
Don't play this game unless you're using CHROME as the author mentions. I had 100% bug failure using firefox and it was really annoying when you get below level 12 and it keeps freezing, usually after killing something with fire. I gave up with firefox, downloaded and used CHROME and only saw 1 bug, which was the no doorway in a starting room, but clicked the walls and it appeared.
I never found anything special after clearing level 4 for the cold dungeon, but I didn't clear levels 2 and 3 since I was running out of the necessary potions. Didn't try with the fire dungeon. Was there anything special except experience and usual loot?
Didn't give it a 5 just because of the extreme difficulty using any browser except Chrome. I'd vote for no save except on level 8 and 12. Part of the excitement is knowing death is permanent, but it's not always easy to sit down for half a day to finish this.
Thank you for creating it. The only thing I can think of to add is having your character change appearance based on what they are using.