So played it through in about 5 hours. Story is, naturally, amazing. The first and final thirds of the game are fun, the ending leaves you speechless, but the middle part starting where you
go to the timeline with the Vox rebellion and then ending where you going to the future (the future part is pretty awesome)
is weak in that the level design is fairly boring and linear (at least I didn't notice many side-paths to explore) and it's just "let's pump as many enemies as possible at the player".
I eventually dropped the difficulty to Easy during that part just because I was bored with the fights and just wanted to get to the next character scene. It needed more of everything plot and world wise that makes a Bioshock game fun, namely more interesting environments and lore-and-character developing audio diaries, and pretty much completely lacked both of those. Elizabeth only seemed to make comments when inside elevators during that part too, instead of the usual environmental comments, which just added to the poorer production quality feeling of the areas. Maybe I would of enjoyed it more if I just played the whole game on that difficulty...
They even do the cardinal sin of having a boss repeat itself with no real variations, and that particular boss is fairly bizarre and out-of-place in and of itself. I mean, really?
A ghost that summons more ghosts? Did she get summoned from the Diablo universe?
Also the existence of Vigors felt out of place. It seemed very "Bioshock did it with Plasmids, so BioShock infinite has too as well". They just didn't feel very well integrated into the setting.
But the game as a whole, both the parts I liked and didn't like, and taking the plot's general "awesomeness" and it's ability to make you care for Elizabeth into account...I'd give it an 8/10. Which I call a damn good score.
8/10 should mean exceptional.
9/10 should be near perfect and hit almost every note beginning to end. My lack of enjoyment of that middle part is all that stops Bioshock Infinite getting this for me.
10/10 is not only a 9/10 but also redefines a genre and/or brings something new to the field, and you'd only expect one or two per generation per genre. This is why I'd say Portal 2 is a 9/10, but Portal is a 10/10, but still say Portal 2 is all in all the better game (and Portal is all in all an amazing game).