Which version are you playing? I've played the PS3 version, and you always control the actual character, while you only have to trigger murphy's actions with a button, he moves automatically. Works 99% of the time fine.
The Vita version however, you control Murphy with touch controls, just like you say. And yes, sometimes the AI player acts like a retard, which is especially frustrating if you're trying to 100% al levels. Another problem was that sometimes my fingers obscured the obstacles lol. Overall it felt like a cheap mobile game...








