Couldn't resist for the free version, too much free time.
Mainly I'm a bit sad because of how the mines work and your level ups. I would prefer to have more uses for skulls rather than only buy food.
I kind of think that directly sleeping in the cell and training needs a buff to compensate a change over what you can do with skulls. I would prefer to buy lessons from other characters, in fact it would make sense that the paladin teaches iron skin, the alchemist teaches charmer, Goren teaching endurance and Shyael tongue twirler (and in the future stealing too).
If you give an appropiate price for the lessons it would feel much more natural rather than "level up choose extra". I think the level 1 with a cost of 10 skulls each one (except the paladin who will ask 20 being 10 a donation to those that need it) would be quite appropiate.
Level 2 would feel appropiate around 80 skulls I suppose, you need to eat too so... 100 may be too much to ask except again with the paladin, this time with extra 20 as a donation for the cause.
Personally I think the mines need a better control because by save scumming you can be level 3 before you fight in the arena and having taken 2 perks. In fact it would be appreciated that some places regenerate each day so that you can mine more, the first "mine zone" I can easily clean it in two days, but the funny thing is that the second mine zone I could still clean it in 2 days, had an extra day in which I did nothing at all, just enter and leave because I had nothing to mine.