MORALS AND IDEALS
As most of you know, this game was basically announced as an AAA game with next gen graphics, and ended up a (at the time) bug-ridden B-list game with last gen graphics. Many people were understandably upset about this, especially those who pre-ordered. If you don't wish to do business with a company that found itself in a lawsuit claiming false advertising, more power to you for your ideals.
I played this in Jan 2015 after some massive patches, and after the game was on sale for $5. At this point, I experienced the game as practically bug-free, except for once when I had to revert to a checkpoint because an in-game button wouldn't work, and the astonishing fact that the game still won't let you go: When I quit the game, it is immediately restarted (wrong exit code or something?). Restarting Steam too helps, but it's a bit ridiculous. On the upside: no game-breaking or fun-killing bugs while I played.
The game is pretty straight forward in that there are no optional side-missions, and the level design is such that in campaign mode, it is extremely rare that there is more than one way to get from A to B. Gameplay-wise, it's a squad shooter in that your avatar is hardly ever alone, yet you cannot give orders to non-player squadmates. Groups of 1-5 players each can face off in various aliens vs marines modes; for this, you can configure the look and loadout of your avatar (including male/female - there's also a Movie Characters DLC with 4 chars none of which is female. Maybe Ripley was too expensive to license, but where's my Vasquez??). The campaign is open to 1-4 players, but incomprehensibly, players can't configure their avatar; they're assigned a premade one even though only one of them appears in cut scenes or has any dialog. (The loadout however is still configurable.) Proceeding in the story or meeting challenges results in more customization options (some purely cosmetic, others ways to make the various guns more powerful, though squads with players on different levels seem unproblematic).
Apart from Steam Achievements (some of which are for the sole story DLC, Stasis Interrupted), ACM features challenges.
The challenges suffer from having a required order -- you won't get credit for a challenge that isn't up yet. Also, there are challenges that require other players outside the "Versus" challenge category, implying that as a single player, you can't even finish the "General" category. Meh.
You'll revisit a lot of the story for the Challenges/Collectibles, but since you can only jump to Chapters but not savepoints within them, you'll waste a lot of time getting to the scene you need.
The graphics are serviceable. The texture resolution could be a little bit higher, but then, it could always be a little bit higher. Considering that this is after a 4 GB patch that included better textures, I'm scared to imagine what the game may have looked like at release. Now however, it does its job; as long as you don't expect Alien: Isolation, you might be satisfied; just keep in mind that this is Dead Island to Isolation's Dying Light. There are some enbseries presets for this game that amplify bloom and color grade in favor of blues, as you would expect from an '80s movie (especially Aliens). Apparently, one preset even add a "VHS look". I find this to slightly improve the graphics, but only so much (nothing like the drastic results I had with presets for e.g. Fallout New Vegas etc.); it may or may not be your thing.
We meet pretty much everything you'd want from an Aliens game in ACM: loaders, dropships, the Sulaco, various types of alien including the queen, and hey, you get the shoot the pulse rifle. (I'm easily satisfied that way.) You also get to deploy auto-guns, use the smartgun, etc. You get to shoot aliens in Hadley's Hope on LV-426, in the space jockey ship, on the Sulaco, and various other beloved sets. You pay for this with some inconsistencies -- some understandable and even welcome (for you to frolic in Hadley's Hope, they had to downgrade its destruction level from vaporized to condemned); some incomprehensible (the dropship and consequently the APC look subtly, but noticeably too narrow, and so does the Sulaco's hangar). I remember Aliens very, very fondly (while at the same time not being enough of a fanatic to notice that e.g. the individual crewmembers' cryo-sleep booths on the Sulaco weren't in the same order as in the film, or that someone's locker opened to the wrong side), so for me, the set alone was worth the price of admission. (The engineer's ship is a bit boring, but then, we never really saw much except for the space jockey and the eggs in Alien, either. It's big and empty, and I guess it's supposed to be.)
The story isn't outright horrible, and it ticks the expected boxes (some people get "impregnated", some people get cocooned, lots of people and lots of aliens die; the marines are good, the company is bad, and the usual gear is used etc.), but it is hardly material for a movie that might stand alongside Aliens. The main plot motivates a lot of shooting, and traversal from one set piece to the next, but does little for me beyond that; the story ends very suddenly, giving away what might have been an emotionally satisfactory coda; and it can be a little non-obvious in the heat of battle which of the identical twin ships your captain is on at any given moment. It's not horrible, but it could have been so much more. It could, arguably, also have been longer, with the main campaign clocking in at less than 10 hours.
Some plot points are cleared up in the prequel DLC "Stasis, interrupted", thus continuing the worrying trend where you have to pay extra for closure as it's no longer part of the main game (cf. "Broken Steel" for "Fallout 3", Tina's DLC for Borderlands 2).
So, is it justified?
As an excuse to revisit beloved sets, it certainly is. As an excuse to do much shooting with fun guns, it is, too. As plot and production values go, it is a wasted opportunity, though in all fairness not on the level of Alien^3 which instead of taking us to earth, or the home planet of the aliens, or that of the engineers, gave us the stakes of the lives of few dozen ugly killers and rapists, and then didn't let us root for the alien because the SFX looked so pitiful.
It's probably one of those games where you best bring your own friends if you want to make sure you'll get to play. While I'm normally a "strictly co-op" girl, some of the vs maps and modes were surprisingly fun. Due to the lack of maps, you'll probably need DLC quickly: Bug Hunt is a fun new mode with 3 maps that has a friendly community.
If you want to shoot fun guns in familiar, beloved sets and you can get the game on sale, ACM should be fun for a few hours -- as long as you don't expect a AAA title with brilliant writing and next-gen graphics, which I'm sure nobody does after the massive backlash. It's definition a can-have, if not a must-have. In the end, it's down to whether you believe that after the massive backlash and financial losses, the industry got the point that all the foul play of the early days wasn't on, or whether you believe we still need to make a point. In the former case, you may want to kerb your expectations and give it a go; in the latter, you'll be right to give it a pass.
Steam forces me to tick yes or no, so I'll go with "no", by a whisker, simply because while I had fun, it falls short of its announcement, there could have been more multi-player maps, more/better plots and graphics, etc. -- the patched version is never horrible, it's actually fun enough, but it's also noticeably lacking, just a bit, but in every category. "No" to lack of closure, "no" the charade around its publication, "no" because of what could've been, and now likely won't ever come to pass, or at least not for a very long time.