I have the RPG (as yet unplayed, not uncommon for me) and I’ll spin it two ways:
On the one hand, the game was largely built around one-shot/short “cinematic mode” scenarios. You’ll start with a handful of characters (generally more than there are players) and will almost certainly die. Extra characters are NPCs and are handled by the GM until a player dies, at which point control is handed to the (dead) player. Leveling up and long-term character development take a massive back seat here, as the scenarios will dictate many of the decision points, and characters are pre-set with backstories and ulterior motives. Treachery can be expected. You will break from stress and mess everyone up (and sometimes perform amazing feats) due to it. Contrary to what was mentioned earlier, this is very much a roles-before-rolls kind of game. Role playing your characters well is paramount to a good experience and the dice aren’t expected to come out unless something exceptional is going on. This mode is expected to be played over one or a few sessions to completion and is IMO the entire reason to get this game.
On the other hand, as an Alien fanatic, there is the campaign mode, which is entirely free-form including character generation, long term character development and leveling, etc. Ulterior motives, stress, backstories are all expected to play major roles in the game, but they play out over the long term with XP incentives for making meaningful progress toward these goals/ambitions each session. These things can change as the campaign rolls on and they get achieved or become irrelevant. The book is an absolute treasure trove of Alien lore, and a true fanatic will be able to plumb it for endless fun scenarios. I am a die-hard Alien fan, but a casual one at the end of the day, and I wouldn’t know where to begin with an Alien campaign while expecting to keep it tense/scary/interesting. That the mode is there is nice, but the Cinematic mode is the meat-and-potatoes of this one, IMO.
It’s a pretty easy ruleset to understand, with what I think should be a pretty minimal teach for any players at the table (for cinematic mode, anyway). With the scenarios handling the grunt work, and so much dependence on PC interplay, I’d expect it to be a reasonably smooth game for the GM, too. Cinematic mode is a big reason I got this one, as it feels like I might actually have an opportunity to table it.