ok im really late to add to this but i gotta share my two cents because im opinionated.
I played the hell out of both of these games and about 3/4 of the way through infamous i got really bored and fell asleep. its increadibly repetitive, the player's powers handle like a golf caddy on pogo sticks and the story is shit. there are no powerups to speak of and its very short. you spend most of the time in a sewer, and each level in the sewer is a tedious repitision of the last. the only good parts are when you are infiltrating huge garbage compounds which are rare, and aiming is clumsy and enoying.
Prototype. the story is shit, alex is a retard and the map was stolen off spiderman3...BUT the fighting is epic. you said you only used the tenticle thing well clearly you didnt explore the fighting dimentions well enough because if you did you would find that you would eventually find yourself hurling yourself around flicking rapidly between powers for (not just creative but) nessesary enemy rape. if i stood around using the whip all day, monstors would skullfuck me. i got a couple of hundred hours of game play out of this, because i have no life and its mindless carnage and it lets me blow off some steam between shit/pressurising games.
I dont get why your always critisising games like they are movies or literature, sinse when did story ever fucking matter in a game. the level of emmersion is down to the player, not the knob jocky who wrote the story. the storys are usually rippoffs from movies anyway, its called the design method and its used in every commertial application imagionable, and its within chimpanzee capacity. If you make a game all you have to do is make people like me smile while i maim sombody who didnt deserve it and throw tits in my face and remind me im awesome for clearly being braindead.
prototype is one of the games that recently came out and was under-rated. you kill thousands of people with an initial thrill which is rare (but admitidly this sensation disipates), the engine uses up so much ps3 CPU you can smell burning plastic coming off the heat sync, your guarenteed a good 100 hours of gameplay if you get into it, the aiming system is refreashing and accurate while not sacrificing the challenge of target aquisition. And one of the best and overlooked qualities is, you dont rage quit and its also a level of cognative activity that keeps you busy for hours.
/rant