Picked this up yesterday and am currently working my way through Chapter 5 already. Feels like home again.
Interface is basically the same with information shown either by readouts on your suit or huds projected in front of your character by the suit. Weapons are a bit different since they've received an upgrade in look, but the feel of the plasma cutter is the same old limb-slicing goodness. So far, all I've unlocked is the harpoon gun, which works like it sounds, allowing you to pin necros on the wall, then follow that with an electric shock that also does AOE damage.
You spend the first few chapters without a suit, and don't end up with even the plasma cutter for a few crazy minutes. Luckily for Isaac, he's able to use Kinesis to grab objects (like metal cabinets that smash to let you chuck stabby supports and decapitating shelving) and severed limbs to use against the necromorphs trying to mow him down. Makes for some great "oh shit" moments as you frantically look around for anything not bolted down to take out the crazy face-stabbers trying to...well...stab your face.
The oft-mentioned vomiters show up, which are basically the standard necro with a distance attack that slows you down and slowly eats away at your health. Also encountered was a group of crazy tweens that swarm you like you were a Bieber, those little floppy things that jump on you, the explody-limbed jerks, the resurrecting manta-ray thingies and a really large and angry dog monster who wants to eat you.
Environments are claustrophobic as usual, but being in a city in space gives it a BioShock feel, which is perfectly acceptable for creating that lovely sense of dread. Zero-g hasn't been used much yet, but from what I've experienced, works pretty easily with the control system set-up by the game already.
Hacking has changed, being more of a "find the correct rumbly bit" instead of the "connect the rumbly dots" of the previous game and is actually done by Isaac shoving his whole arm up into a console and fiddling around while you go through the mini-game. Also, hacking is how you end up getting your kinesis, stasis and your first plasma cutter, so it ends up being a better fit by giving you a more visceral connection between the game itself and the mini-game.
Still going through the game, but again, it's just like coming home again if you've played the first. Everything you loved, but with enough tweaks, changes and full-on expansions of ideas to keep you interested.
Highest possible recommendation.
No multiplayer yet, as my connection still sucks.
