Thanks for the compliments! Happy to hear the game keeps you returning here although you're not the target audience, that's awesome!
The final boss fight gets pretty hectic, but with time and the right gear I'm certain you'll beat it.
For the stretched character portrait, embarassing that I'm only now noticing it, I got it fixed now.
And sorry to disappoint but there isn't another track on a different level. The difficulty levels don't change the stage itself, instead they increase material and gold gains while making the run more challenging in various ways. Thanks again for the feedback!