Good idea, but...
I'm seriously trying to avoid bankruptcy here, as there isn't a really steady income, the best way to make money I've found is to scrape weak labrats mine had defeated, as miners keep dying and I run out of money just to sustain the beast.
Also, income from arena battles is way too low, at least compared to the money you invest to defeat one of your opponents.
Tipically, my game ends up with me being in limbo, fearing to move due to the unclear "monster lever" advice, avoiding sending people in the mines because they die in a ridicolously short time (I mean, accidents happens but seriously, this rate would have been ridicolous even in victorian age).
Also, the lack of a proper save game feature greatly cuts longevity, as the beginning is a trial and error process, and I don't want to begin a whole new game just because I choosed to move to the left to see what the hell was there and the be raped by a "level 2 monster".
To summarize, it just needs less casual encounters and some way to gain a steady income, at least at the beginning, also a slightier higher reward for arena and a lower food price.
Oh, and those miners. Seriously, you really need to dramatically drop the death rate.