Apocalypse Then

The PC mod Long War
overhauls the reboot
experience considerably

XCOM is one of those games that if it weren't for an enthusiastic endorsement from a friend I probably would have never taken any interest in the the series.  Thankfully, I did play the original, along with the sequel, Terror from the Deep, and the two new reboots; Enemy Unknown and Enemy Within.  I also played the entry in this turn-based strategy series that is the redheaded stepchild of the bunch, XCOM: Apocalypse.

Unlike other mainline entries in the XCOM series, Apocalypse allows for battles in real-time with the option to adjust the speed (and even pause the action to issue orders as needed).  Squads are split into six fire teams of up to six soldiers each (for a total of 36 units!).  In an effort to streamline gameplay, players can issue orders to squads rather than individual units.

The air war also takes place in real time with the possibility of engagements between multiple UFOs and XCOM craft.  Similar to the setting of Judge Dread, humanity has gathered into a single mega-city protected from the polluted wasteland of the outside world.  The cityscape acts as a backdrop for the action, but features a number of science fiction curiosities such as skyscraper-sized hydroponic farms, a star port, and public schools that transmit knowledge directly into the brains of their students (rather than relying on things like lab work and teacher lectures).

There's some interesting fan fiction
that has influenced the reboot in subtle ways 

There are a variety of factions within the city as well, ranging from political parties to corporations (that manufacture goods and provide services), all the way down to gangs (one of which will sell incendiary grenades to XCOM if befriended).  A cult is also present.  Similar to Exalt, they are enemies of XCOM and allied with the aliens, but can be raided.  On one occasion I remember looting a sizable amount of "psiclone" (a cybernetic narcotic) from a cult temple which I then sold for a tidy profit.  Of course, one of my bases was later attacked in retaliation by a combined force of cult members and aliens.  Some of which were armed with XCOM made equipment I had regrettably sold on the grey market.

It's important to note that the aliens are interdenominational rather than extraterrestrial this time around.  Incursions happen when UFOs pour through one of several dimensional gateways floating above the city.  The crux of the endgame revolves around building craft that can travel through these gates and take the fight to the aliens.  From there players can launch highly destructive raids on alien facilities including UFO construction yards, incubation facilities, and other logistic centers.  So, why isn't this the greatest XCOM of all time?  Well, there's a couple of reasons...

Notable sci-fi artist Tim White created
sculptures which regrettably are only
seen in static screenshots  

The aforementioned city factions, while intriguing in concept, are woefully underdeveloped.  Most don't interact with XCOM at all unless it is to demand recompense for property damage caused by the player.  Graphically, the game is also sub-par, even by the standards of that time.  The retro-future look the developers were going for never quite worked on-screen.  Some of the aircraft look nice, but the aliens are particularly fugly.  Most are little more than muddy looking blobs of blue, orange or purple, whose forms can be only be identified in any real detail after an autopsy report.  There's also no classes although players can recruit androids or hybrids in lieu of humans to get a wider range of unit stats.  That said, most XCOM personnel are pretty much interchangeable mooks defined by load outs instead of skill sets.

XCOM: Apocalypse may have simply been too ambitious for the era in which it was created, but an opportunity exists to capitalize on it's strengths with the upcoming dystopian near-future setting of XCOM 2.  If the developers can find a way to take the best aspects of both new and old, then this soon-to-be-released entry in the franchise has the potential to outshine all the rest.  Good luck Commander!...I mean Firaxis.  

Right...moving on...