It's a great concept. But the developers obviously only want one thing. Money. The regular version is riddled with ads. There is a completely ridiculous energy meter. Oh, and gems cost ridiculous amounts of money. Unless you want to spend all day watching Ads to get a decent weapon, you're screwed. All of this harassment is to get a better version, and unless you don't want to pay money to people who harassed others and exploit people, you are out of luck.