Ask me what my favourite game of all time is, and I'll probably say Planescape if I want to seem arch, TF2 if I want to seem contemporary, Peggle if I want to seem kooky, maybe Dungeon Keeper or AvP if I want to succumb to nostalgia. If I'm feeling balanced and honest though, there's a very strong chance I'd say UFO: Enemy Unknown, the first X-COM game.
It's a game that's been endlessly... let's be generous and say 'homaged', both commercially and by dedicated fans. Nothing quite seems to recapture it, sadly - either it's too different, or too similar, or, most often, it pulls off the underlying structure but doesn't bother with the gentle surface charm and humour of the old DOS dear. UFO: Alien Invasion, though, is one of the more impassioned and direct clones - a community effort that's entirely free, and built upon the Quake II engine.
Version 2.2 is just out, and it's a beefy old update. Specifically, it includes these things: "Air interceptions; UFO recovery; UFO crash sites." Which you may remember as being three of the more important elements of an X-COM game - meaning Alien Invasion has gone far beyond the ground missions other remakes have stalled at. Playing briefly around with it, while the graphical approach can best be described as "adequate", it's clear there's a lot of potential for this to eventually become the game X-COM fans have waited for over the eleven long years since Apocalypse, the last in the series (a couple of ropey spin-offs aside). It's a better effort than its rivals, both commercial and gratis, in many ways.
Except for the interface, which is absolutely horrible. I did try to think of a polite way to say "horrible" while still clearly meaning "horrible", because I do hugely respect the incredible efforts of the team behind Alien Invasion, and I'm dead excited about what they're doing. I failed. It's quite the brick wall to my giving this serious time. I am a fussy, fussy man however, so I would certainly recommend that any X-COM fan gave this a try - your tolerance for errant button placement and shonky scrolling may well be greater than mine.
One change from the classic formula I've certainly enjoyed so far is the new email system - the research team drop you messages with proposals on what to investigate next. This props up the in-game fiction, provides handy pointers on the most sensible way up the tech tree, and resolves one of trad. X-COM's distracting bugbears - scientists would sit around doing jaff all unless you remembered to go tell 'em what to do next. Now they actually seem interested in doing something to earn their eyewatering wages.
Alien Invasion has also, perhaps inevitably, gotten me thinking about the new X-COM game the artists formerly known as Irrational are/were rumoured to be working on. I don't believe it was ever confirmed, so there's every chance it'll never happen, of course.
Certainly, post-Bioshock, it seems oddly unsuitable for them. X-COM, traditionally, is a game of mechanics and tactics, not narrative and philosophy and meaningful choice and sparkly-graphicked hi-action. A remake of it seemed to fit the studio pre-Bioshock, when Irrational were most known for the rather more low-key Freedom Force and SWAT 4, but their reputation has changed utterly since. With the world doubtless looking to Ken Levine and co for their next game to also be one of controversy, ruminations upon the nature of freedom and a killer soundtrack, I can all too easily imagine a new take on X-COM's ace but stoic mash-up of strategy sub-genres being pushed aside in favour of another action-heavy headline-grabber. If they did make an X-COM game, I can't really see it being much like X-COM.
That's just me being paranoid though - I'm probably way-off base. I'd defintely love the rumour to be true - as much to see Irrational/2K fly in the face of expectation as because I desperately want to play a shiny new X-COM.