There was some stuff I liked, and stuff I didn't like:
Liked:
1) The fact that we at least got an explanation for how everything led up to the main game. It's an explanation that's pretty goddamn stupid, but it's an explanation nonetheless.
2) All the continuity nods were quite nice: Lisbeth doing the self-destruct sequence like the Nostromo in the original film, her holding the chestburster like Ripley in 3, the audio logs giving a bit more colour to the proceedings et al. These were the best part of the main game, and they're one of the best parts of this one.
3) There do seem to be some decent jump scares, due in part because of the soundtrack (which is also really good).
4) They gave Lisbeth Sanders, a character who exists for all of half-an-hour of gameplay, more characterization and depth than anyone in the main plot. That's an achievement by itself.
5) The Legato, W-Y FTL ship and cave levels are all quite fun to fight through (I don't count the Sulaco or most of the LV-426 levels because they're just reused from the base game).
Disliked:
1) The retconning/rewriting of the A3 opening. When a soldier knocking a civilian into a cryotube and closing it elicits unintentional laughter instead of interest, you know something's gone terribly wrong. I can't get over what's worse - the flagrant attempts to shoehorn this version of events into the film's timeline, the wonky "fight scene", the dull surprise Biehn utters when seeing Ripley for the first time since waking and the general lethargy of the sequence. That said...
2) The Fury 161 scene is worse, if only because it makes Hicks look like a complete idiot for not yelling at Ripley when she's up on the platform. I swear, it's like they made Hicks the "Forrest Gump" of this game - he has to visit every goddamn location from the trilogy. The Sulaco (again), Fury 161, the Derelict, Hadley's (again).
3) The whole "race against time" plot doesn't work because it's a foregone conclusion. There's no tension or sense of interest because we already know what happens to Ripley, Hicks and Stone.
4) There's still some clipping/lighting issues with the characters and enemies, even with the patches.
5) Some of the serious moments end up looking hammy, like the aforementioned "A3 revised opening" sequence, the soldiers holding the Queen captive at the end of the DLC and characters in the opening stage falling over and dying for no discernible reason.
Overall - too little, too late.