Some thoughts and criticisms:
All other idle games I've played calculate off-line gains. That would be the greatest. Without this it's far too slow-going to maintain interest.
This is a very slow-going game. Changing the first retirement/veteran upgrade from ilevel 100 to ilevel 50 would help massively.
More class-specific bonuses would be nice.
Magic find effectiveness seems to diminish greatly the deeper I go. Might just be kill speed but seems to be more than that.
It would be nice if achievement bonuses were permanent, although the gem bonuses every run is greatly beneficial.
You can change this now in version 1.3