I never played the original XCOM; despite that, I love the genre, and played more Fallout Tactics and Chaos Gate than I care to think about, as well as more modern games like Silent Storm. This is to say that I'm viewing Xenonauts on its own merits and not colored by any association with its spiritual predecessor.
There's a lot to like here, and some parts of this game I'm really fond of. I like the setting, with retooled F-16s and MiGs giving things vague Independence Day vibes. The strategic game is fun, establishing bases, managing personnel and research projects, and dispatching interceptors to engage UFOs. Some might find the micromanagement of every soldier and every F-16 a little fiddly, but I enjoy it. The overall atmosphere is intriguing and the basic premise of defending Earth from alien scum is a classic.
Unfortunately, that's where the good ends. Manual air combat is lackluster, feeling unresponsive and offering few options other than to bring more firepower to the table and win the resulting slugging match. This is only a minor complaint, however, as it serves its purpose and air combats can be autoresolved if one wishes.
Ground combat is where I was truly disappointed. Again, I don't care if it's "faithful" to a 1994 game or not, this game came out in 2014 and those are the standards I hold it to. At first glance, it seemed a little reminiscent of Silent Storm, with action points (TUs) and Snap Shots, Aimed Shots, Bursts, etc. It lacks Silent Storm's depth, however, and yet also somehow manages to exacerbate Silent Storm's worst flaws of unfathomable line-of-sight/vision/detection rules, a tedious RNG overwatch system, and an AI which knows just how to exploit both to maximize player frustration. Added to this is a downright awful movement system, which punishes you for any kind of movement and making many tactical maneuvers virtually impossible.
My favorite moment thus far is when I was stacked up to assault a downed UFO's cockpit. Because of the frustratingly punishing movement/TU limitations, only my two soldiers immediately on either side of the door had enough movement to open the cockpit doors, run inside, and still get a shot off at the occupants (grenading was impossible, both because of the way the doors were set up and the even MORE punishing TU requirements for grenades). I had to make sure they ended their turn at the doors in order to get a full turn's movement the next turn, meanwhile, the rest of the squad covered the door from behind cover elsewhere. So, naturally, during the AI turn the aliens pop out of the cockpit to take a shot and then pop back in, Silent Storm style. During one of these, one of my guys gets an RNG interrupt - which I have no control over - and unloads his machinegun... directly into one of my stacked-up assaulters, despite being BESIDE the door, out of the line of fire! KIA.
Maybe the game is going for some kind of wacky "Haha, see how many hapless idiots you can turn into cannon fodder" theme, but the detailed service records explaining that my soldiers are Soviet VDV or British SAS with combat experience in Northern Ireland seems to undermine the notion that my soldiers are supposed to be high-mortality idiots intended to be thrown at the aliens like disposable meat shields.
I like that the strategic layer and overall atmosphere of the game are so much deeper and more intricate than the new XCOM, but the tactical gameplay is so painfully backward that it drains any real fun from the experience. Masochists and 1994 nostalgists might get a kick out of it, but anyone else is advised to just go reinstall Fallout Tactics or Silent Storm instead.