Short hint to farm gold: Needs time, but you get results very fast. It doesn't make sense to beat bosses if you can, because you also need time to beat the next levels. So your progress is slow. Go back one stage and farm. Go offline, make other things between. Now level up until each block is destroyed really fast & go offline again. Win. Reason: You gain more money by beating blocks really fast than needing many seconds to destroy them to the next boss.
Was at Miniclip today and the announced a "brand new" game: This one. Thought, I'll play it one more time but then.... Something was changed: They censored it! No blood! No dismemberments! No suicide attackers... What a shame. Good to have the uncensored one here.