Those reviews are infuriating and confusing - more from the perspective of this game being totally translated over, in terms of (most importantly) gameplay, content and extra mission DLC yet it doesnt compare to home consoles/PC so it's marked down (I'd argue it does compare to the console versions). Seriously, what the fuck did they expect? There are frame rate dips at times, yes, but none game breaking or affecting the gameplay in my opinion. The line about feeling like the character is underwater is, like I said earlier, just straight out bullshit.
Does the game play well? yes. Is it one of the largest, most content rich handheld titles ever? yes. does it look and sound great? yes? 5 out of 10.
I swear that latest update has made the game play smoother. Maybe it was a placebo update!