I'm a good 8 hours or so into Enslaved, around chapter 7 I think. I also played that horror of a game FFXIII for about 8 hours.
Enslaved is so much better than FFXIII I don't know where to begin.
Monkey (the guy) is so much fun to play when he's jumping around, swinging, climbing, etc. The size and height of things is impressive to the point where I get a sense of vertigo.
I'm playing on easy and having a blast. I can see how in this game, difficulty setting could make a huge difference if it makes it easier to fall. The boss fights have been great (I can't even think of a memorable one in FFXIII).
Trip (the female) is a great character in her own right. She's the "brains" of the two. While you never play her character, you do carry her around, throw her around (fun), and use to to distract Mechs, and tell her when to run between cover spots, etc. You can easily give a shit about the characters (unlike FFXIII).
The facial expressions in the game are great during cut scenes which integrate extremely well into the game. They're not long and used very well (unlike FFXIII that has way too many cut scenes, interrupting the game flow)
There is some RPG part of the game. You collect glowing orb thingies which allow Trip to upgrade Monkey's weapons, health, shields, special attacks, etc. I've been concentrating on Total health and Health regen, so haven't seen much other stuff. You're two ranged attacks (which require limited ammo) are Plasma and Incinerary. The various mechs have shields etc that require some strategy in taking them out. The battle mechanics aren't too complex but there's enough there, several melee attack types, dodging, shields, etc, to make it interesting while not overwhelming so you can focus on the fun and adventure in the game instead of dealing with too many combos.
The characters are interesting. Monkey sort of grows on you from being a brute, to having a more rounded personality. Trip is refreshing in that she can take care of herself (well up until Monkeys acrobatics and strength are required). She's resourceful.
The two main areas in the game I've seen have been outstanding. The large city as well as a post apocalypse town built with defenses are worth taking the time to look around as you follow the completely railed path. The size of the areas loaded all at once into memory are huge, and as you work your way through an area, it's cool to look way back and see where you began sometimes. Also, the height gained in some areas is impressive once you look back down as where you started.
The puzzles aren't too hard but that's a good thing. Monkey typically has to find a way around things. Sometimes he needs to direct Trip to do things. There are very few times where timing is critical. Thankfully when Monkey's climbing, he can usually take his time but sometimes he'll heave Trip across a space and she'll barely make it and if he doesn't get over fast to help her up she'll fall or something. There's also a few times where grip spot, ledges, etc are unstable so you have to hurry but not too many.
Great game. My favorite since Borderlands and Mass Effect 2. I don't know how long the game is but the first 7 chapters/8 hours have been fun, with changing scenery and new challenges/puzzles/boss mechs. While it's only got a small amount of RPG elements, it's enough to matter so you can customize how you play Monkey. This is not an open world game. It's like FFXIII (on rails) but really entertaining with outstanding voice acting and an interesting world to be in. There's no giggling dumbass baffoons, just two characters. One with a purpose, and one being used by the other for that purpose. The story makes you want to see what happens between the two.
Good stuff.