PEGI rated the game PEGI 18 for "Extreme violence." The BBFC rated the game 12 for "moderate fantasy violence." It's a BBFC 12 rating that you're seeing on the UK pack-shot.
In the UK, publishers can go with either PEGI or the BBFC - and in this case the publisher chose to go with the BBFC, who took a far less hysterical approach to the game than PEGI did.
You can read the BBFC's detailed reasoning on their website, but essentially they decided that (quote) "the alien invasion premise places the game and its violence in a clear fantasy context."
Also - and I respect this a LOT - the BBFC reasoned that the game's thoughtful and strategic nature mitigated in its favour. Quote: "The violence is balanced by the significant strategic aspects of the game, such as the building of installations and weapons, and by the decision-making on research into the aliens, without which the player cannot battle effectively against the enemy. Accordingly, the game is not focussed solely on fighting and killing."
I am normally quite a cautious person when it comes to the content of films and video games (being the mother of three children aged 12, 9 and 7, all of whom have access to PC and console games, means that I pay a lot of attention to such things, and always pre-view films and pre-play games before handing them over to my children).
In this case, the PEGI 18 rating really *IS* a massive over-reaction to what is, in fact, very unrealistic and cartoonish violence. OK, soldiers and aliens spray a bit of blood (green blood, in the aliens' case!) around when they get killed, but it really is so brief and unrealistic (the dead bodies themselves - which are shown very briefly - aren't even visually injured, and nor are any soldiers/aliens who get shot but not killed) that rating it 18 seems extraordinarily heavy-handed.
The BBFC's rating of 12 is spot-on: the game does indeed include nothing worse than "moderate fantasy violence", of a very non-upsetting, non-realistic nature. The soldiers don't even make any sounds when they get shot or killed, and even the aliens (with one or two exceptions, who make brief alien-like "squealing" noises when killed) typically make no sounds, and exhibit no wounds, when shot or killed.
I'm pretty keen on preventing my children from seeing/playing any games which might upset them at all, and I have no problems with letting them watch me play XCOM EU - or even have a go themselves, although the strategic elements are a bit beyond them at the moment. Violence-wise, they are not troubled at all, and nor am I, since the "violence" really is (deliberately) so very fake and non-frightening.
NB : It is possible that the presence of (very mild) swearing in the game may have influenced the PEGI rating. I do know that, typically, the American censors are more worried by "bad language" than their British/European counterparts, and are more likely to uprate a film or game if it contains swearing. It may or may not be relevant to mention that XCOM EU does contain a few minor swear words: the game uses live voice-overs, and these voice-overs may include words such as "Damn" or "Hell". There is no swearing any stronger than this in the game (no classic "four-letter words") and no references at all to anything of a sexual nature.
Thanks for the info above. I was a bit upset when i ordered off amazon a 12 rated game for my son and it came with an 18 rating on the front! not as shown in the picture on amazon. I was going to send it back and still might as trying to explain the above to my wife might be beyond me!!!
The UK copies shipped with the PEGI 18 ratings on it. Honestly the BBFC's reasoning for giving it and the original a 12 was a lot more sensible.. I can see why it has been given an "18" but I don't think it's required.