Flawed DX11 implementation
I suspected the reviews were partly poor due to XCOM fans being upset it was not a turn-based strategy game. However, I soon enough found out the negativity was not unwarranted and that there were real issues with the game.
For starters, the game was not very stable and it kept crashing. This was apparently caused by PhysX. Turning off physics cloth and particles in the options fixed the problem. Frame rate was also far from stable, tanking pretty often at places for some indiscernible reason. That was pretty surprising for a big studio Unreal Engine 3 game. One would expect better optimization at that level.
The DirectX 9 version of the game seemed to run better but not perfectly either. And it definitely looked worse than the DX11 one. Shadows, for instance, would drop in quality couple meters from the character in a very glaring way if they were not set to Very High in the options. GeForce Experience supports The Bureau but its suggested optimizations did not really help in any way either. It even turned PhysX clothing back on, giving me a crash after a loading screen until I disabled it again.
Poor man's Mass Effect
Gameplay-wise the game is a lot like Mass Effect. Unfortunately 2K Marin decided to not make the combat full-on action but mixed it with sort of strategy elements from the franchise's mainline games. You can queue abilities and commands to your squadmates only via Battle focus, which does not even fully stop time like the HUD screen in Mass Effect. (The default keybinds for shift and space are also backwards when coming from ME2 or 3.) It is quite awkward. And oddly enough your grenades are instead a real-time ability.
The game defaulted to Veteran difficulty which is the second highest of four. I had to lower it one step down to Squaddie after losing all but one of the recruits in the first major mission. It would have helped if the squadmates would not sometimes run into their deaths like absolute madmen. You occasionally really have to babysit them. You get killed very quickly when not in cover.
All the different enemy types are introduced early on. That is problematic for a while as you do not yet have weapons nor abilities specialized at destroying armor. When you finally get a blaster and your support agent his Weaken Armor, The Bureau gets noticeably easier. As my other squadmate I used a scout agent as his abilities seemed the most useful. The engineer one is probably as good but the commando I did not like. His Taunt and Pulse Wave seemed useful too infrequently.
Light on character customization
A rather amusing throwback to Mass Effect is created by one of the squadmate agent voices being Brandon Keener. Every time agent Sue (my support agent) spoke, I half-expected to see Garrus Vakarian when turning around to face him. Maybe I should have renamed the agent as that is possible in the game.
You can also customize the colors of the agents' outfits as well as choose their weapons and backpacks. At couple levels you need to pick a perk from two different choices but all in all the customization is not superb. The Bureau also hides information. It would be nice to know the exact weapon damage (though I think it simply goes up from bullet to laser to plasma) and how large effects the backpacks have. I ended up using Tactician Pack as it gives three bonuses: ability range, weapon damage, and reduced damage taken.
Standard writing with a twist
The game is set in 1962. A sudden alien invasion cripples the US, and XCOM -- originally created against a possible Soviet attack -- is the first and last line of defense. You play as William Carter, a now former CIA agent with a tragic past. He is not a very likable character but you can often pick less rude dialogue lines against his personality, although it does not seem to make any difference -- this is not a roleplaying game like ME.
Given that, I definitely did not expect how the endgame turned out. If you choose not to end the game with a bomb going off in the XCOM base, you will proceed into one final mission with a different character of your choice. I first picked Dr. Weir as he was an obvious choice for a good ending. But I then loaded a checkpoint as I decided I would rather listen to Angela Weaver. (She is voiced by Courtenay Taylor, another Mass Effect acquaintance.)
She was evidently the choice for a bit darker outcome. However, regardless of your choice, the invasion somehow gets buried from public eyes. Which seems implausible. Whole towns destroyed and thousands dead seems like a thing pretty damn difficult to hide even before the Internet.