It's a good game I played for months...it is MGS5. CRAZY complex, I mean there's all kinds of new systems, but amazingly they're introduced at a perfect rate so it NEVER feels overwhelming or out of control. You get something new to play with and it's like "yep, no big deal, I get how this works".
BUT it's a hard game. MUCH harder than MGS4, no difficulty settings, and while it's mostly always fair, plus you can use different weapons and stuff, towards the end of the game I had to give up. Even still I'd say it's worth checking out if you're interested.
As others have mentioned, the controls aren't an issue-I mean they're complex because it's a crazy complex game by any standards, but they work just fine and aren't confusing. (Any competent PSP game deals with one stick fine, since Bend's Syphon Filter games came out.)