Infinity Blade is ...well...it looks like an RPG - but it isn't. It's a swordfighting action game with treasure and leveling up and fantasy elements. There's really no story or decision making or anything like that.
Some people have likened it to "Punch-Out with Swords" and I think that's somewhat accurate. It's fairly simple, you travel from point A to point B killing baddies on the way. You level up your armor and weapons along the way. You get to the mini-boss, and perhaps kill him. Usually you'll get to the last boss on the first round and he'll kill you.
Kill you dead.
But then the game starts over on "Bloodline 2". It loops. So you can keep playing, collecting, fighting, and hoarding as much as you want. Each time you start a new Bloodline, the monsters level up with you. (The last one doesn't, he's high enough already - that's the point).
It's also REALLY pretty. I downloaded the UE3 tech demo last year called Epic Citadel and was blown away, but this expounds upon that concept. I think it takes place in the same setting, actually.
It's not a $1 game. In fact, it's like $6. Even still, it's one of the top selling games around. I paid that much, and I think it's definitely worth it.