The gladiator setting of Blood & Glory (not to mention the app’s title) should be fair warning to parents that this is not a game for little kids. But for adults and older teens who play, this is a fairly well done fighting game. It attempts to tread the path blazed by Infinity Blade, though discards any semblance of story, reducing it to a series of fights.
This would be fine, except the game continually ramps up the difficulty, but your skills don’t advance at the same pace. This puts you in a position of essentially being forced to buy in-game credits to upgrade your skills or weapons (or suffer hours upon hours of defeats to slowly build the skills and earn the credits through gameplay). If you’re willing to spend the money (or walk away when you reach that point) it’s a fine choice. But if painting yourself into that corner is a frustration point, pick up a copy of Infinity Blade (or its recent sequel) instead.