gsergserg
It would be better if you didn't have to restart the game after you don't reach the target for a level - maybe if you just didn't proceed to the next level and only got a fraction of the gold that you earned for failed levels - say, 10-20%?
In light of that, it might be an idea to either reduce the inflation rate in the shop to maybe 1%? Or keep it at it's current levels, but eliminate inflation after failed levels.
Otherwise, it's a good, interesting game.