So I got this over the Winter Sale....
Pretty good! A bit like XCOM-lite. It's a smooth transition from the table top game to a more video gamey Space Hulk. You can play as Ultramarines, Space Wolves or Blood Angels. (Imperial Fists are DLC.) Each chapter has its own campaign of 30 missions or so, and you can play through them all with the same characters for a total of around 100 missions.
I really like the presentation. It's unfortunate this thing didn't have a higher budget because I think it could have put it to good use, although the atmosphere is still set well by how it presents. The Space Hulks are DARK, man, each section lighting up as you enter it and going dark as you leave, so it's very hard to get a picture of the place in your mind and it makes it seem much, much bigger than it really is. Corridors are narrow, and cramped, and the total absence of music (which I was kinda worried about) actually works, the ambiance set by the hissing of steam pipes and the horrible echoing screams of the Genestealers. The Terminator barks and the amount of voice overs is pretty small, but they say stuff when it counts. (Enemies sighted, killed, weapons jammed, Terminators martyred, the occasional move confirmation) and they all sound appropriate. About my only complaint is when you've got 5 Terminators crammed into a tiny room and you've been using the flamer, that plus the ambient lighting does kind of become overkill, especially when you're trying to pick out menus and text floating over your dude. But it's a small complaint. I love how it looks.
On the mechanics side of things, Terminators have classes which dictates their weapon choices, stats, perk-like skills and secondary tech gadgets. While it's not super deep it is flavorful. You can have 1 Sergeant or Librarian, 1 Heavy Weapon, and any combo of ranged or melee guys. Melee guys get a couple different skills from ranged guys, and their starting stats tend to lean toward their specialization. Other than that, and their weapon choices, they're identical. Everyone gets xp from completing mission objectives, and individual Terminators get xp for Genestealer kills. As they level up you get points to spend on their stats and unlock new skills, equipment and weapons.
You can rename each Terminator, and everyone but the Librarian can can pick from a small list of helmets, armors and accessories to customize their look. This part of it feels a little weak, but that's because each chapter gets its own set of armors and accessories. If you total them all up, it's quite a few options, but within each chapter your choices feel a little limited. If they'd made all looks available to all Chapters, and just swapped emblems in and out, the customization would seem more robust. As it is, it's a token gesture.
The missions themselves play out a bit like the board game but with odds tilted more in your favor. Some missions you can effectively sit back on Overwatch and let the Genestealers come to you and die by the dozen. In others, you've got to keep moving your squad(s) while there's constant spawns coming at you, exercising smart fields of fire and good ammo/overheating discipline. There's a Librarian too that brings a few pskyer powers to the mix, just a little something extra to help you succeed. Spawn points become inactive when your Terminators stand close enough to them, and there's ventilation shafts that Genestealers can crawl through but you can't move or shoot into, except with a flamer. Get pinned in a room with one of those at the wrong time and prepare for the hurt. Genestealers show up as pings in the darkness, in a radius around your marines, thanks to the Servo skull equipment they carry. Knowing what you can safely do between turns is a big part of play, as a seemingly empty part of the map can fill up with spawns only a turn away from attacking you, at a moments notice.
Because the hallways are so narrow, single Terminators often get a shit load of xp. The guys heading forward, guarding side passages while others pass, or your rear guard tend to make the most xp. Terminators in the middle of the pack make relatively little. Your rear guard, in particular, can rack up tons of kills. There's no limit on bolter ammo (just heavy weapon ammo) and some maps will never stop spawning guys. So if you've got the stomach for it, you can farm kills all day in the name of the Emperor and xp. Maybe harder missions later on impose time limits and stuff. But in the early game missions (there are also random missions or lightning raids you can go after), you can and should take it as slow and steady as you can. Just like the tabletop, your Terminators take one melee attack and they're dead. There's a stat for shrugging off damage, but I have yet to see it work.
Combat is largely a matter of using Overwatch, but when you choose to manually shoot, you get a couple different attack types, like aimed shots or bursts, to shift odds around. There's several modifiers that go into shooting, with range being a big one. Whether you kill a genestealer or not is largely about how how close they are and how many times you get to shoot at them before they're in melee. Long shots down hallways tend to miss, point blank shots tend to be highly effective. In addition to needing to reload weapons, storm bolters can overheat. The more turns they shoot consecutively, the more likely they are to jam, until they overheat and are guaranteed to jam. When your gun choose to jam (not if) can have a big impact on your Terminator's life expectancy. "Cooling" weapons during your Terminator's turn at the right time is how you keep a good defense up. All in all, combat is juggling several factors in a cramped space, with a good dose of randomness added in. I thought it might get a little tedious, but once you're through the tutorials the game expects you to play like you mean it and I found myself kinda hooked.
There's custom difficulty settings so you can control spawn rates, accuracy penalties and Terminator replacement policies. (Get a lvl 1 Terminator, get a Terminator a lower level than the one you lost, get a Terminator of the same level.)
All in all I had fun and got sucked in. The game looks pretty good (although the bloom and lighting are a little over the top at times.) The interior of the Space Hulk looks great, and is made even more flavorful by the over the shoulder cams on each of your marines. It adds a little something to know you're being attacked by a Genestealer and to see the results through your Terminator's eyes before you know what they are.
This seems like the kind of game that's great for Let's Plays, with a high attrition rate and enough randomness to make those close encounters with Genestealers tense. Taken as a whole the game does seem a little light on the content side (100 missions of essentially the same objectives and dark hallways isn't high quality content), particularly as far as upgrades for your Marines go. A good number of skills and gadgets but not a lot of weapons to choose from, although I suppose they're about the extent of the canonical Space Hulk weapons. (Not sure if you could bring a Cyclone Missile Launcher in the boardgame....or if it's even sane to try to fire it in there.) In terms of being a 40k game, it's done everything right IMO.
There are some complaints about the UI and how muddy the game can look. I agree with the latter a bit, but the former I think is people being lazy and picky. The UI handles just fine as long as you're deliberate. After a couple hours I only had a misclick or two that actually had me yelling "shit!"
As for what to pay for this....$20, which is about what I got it for on sale, feels right. At $30 the shallowness of some of the mechanics and the progression options might leave a bitter taste in your mouth. But for $20 I feel like this is a fun, faithful 40k adaptation that pulls you in with its tense maneuvering in tight spaces and agonizing tactical decisions, with just enough personalization and RPG mechanics to make you care about what happens to each individual Terminator.