Review of the COMPLETE version - Including all major expansions

It's good; get it. On sale, it's a steal; get it!
With all the major expansions this is the essential Civilization game, and a great taster if you are thinking of Civ 6.

For those new to the game, the gist of it is this: You start off with just a city and a warrior unit from which you begin building at the 'dawn of time' and gradually expand your civilzation by gaining culture, advancing scientifically, building and using military, diplomacy, building new cities and buildings within those cities, and building enough 'improvements' to sustain an economy which can maintain the above. Because the map is tiled, each tile yields resources; perhaps a certain amount of food, construction, gold, or even another resource such as horses (needed to build horsemen etc) or iron, oil, even uranium (I don't need to tell you what that's for). As you progress you will find that you unlock more and more improvements, more buildings and more units that you can build, and if you play your diplomacy and development well enough, you will find that you can really start to get ahead of the competition; picture tanks versus musketmen - that can happen. Finally there are wonders which can provide a variety of benefits and a boost of culture. Benefits may include a free worker, reductions in costs for various things or even free technologies! Obviously getting a wonder before other people can therefore be of great importance.

Those are the basics and to new-comers that's more than enough to be getting on with and the AI can give you fairly decent games on a variety of difficulty settings. Equally, there are many, many, many map varieties for your prefered experience - you might want a map with no water, on the other hand maybe small scattered islands: You get a huge amount of customisation here, and it's not to be understated! On the subject of customisation; there are many, many different leaders you can play. The game even offers different leaders for a given civilization in some places; each leader provides differences to the civilization and so as you play with any given leader you want to keep their bonuses in mind and exploit them as best you can. It must be said though, personally I don't tend to notice a great difference between given leaders, the most noticeable thing is their unique units, but even those only last so long before technology supasses them. Maybe I'm just not pro enough. Yet, I play casually, and I enjoy it.

The visuals are readable and clear which really helps for longer play times, and the soundtrack is different for each Civ and varies based on the era you are in or whether you are at war or peace. As the Brits, you may even recongise a good bit of Greensleaves in there too. For new players there is also a decent Civilopedia, essentially a wiki lookup for everything in the game, and even includes larger written backgrounds on each leader and Civ for the historically curious.

Personally, I never really player online or with other people much so I can't really comment on that, but from the time I did spend with other people, I can say that it's an enjoyable experience, even when they march into your territory and refuse all of your offers of peace because, well, they know they are going to walk all over you... or me in this case; we've already established I'm not particularly good at this game.

Another caveat though is that the AI can be a bit temperamental, though this has always been an issue with Civ games and remains one because they can never really act like a human (then again I haven't played at higher difficulties); they might denounce you for no reason, expand erratically, and so on. The final thing to say is that late game diplomacy can be a little... 'off'? Things like World Congress and United Nations - too me they became annoying po-ups every few turns that had little to no impact on the game other than that annoyance and were never really very well explained as to how some people end up with more diplomats than others, more voters and so on. But by that time I have a big enough nuclear arsenal that no matter how much the UN may not like it, I can kill everyone everywhere, like Mr Kim over there only dreams he could.

In summary; it's a good game as a complete edition with all the expansions. On sale the bundle is more than worth it. Civ 5 Complete is a great entry into the 4X genre (4X = eXplore, eXpand, eXploit and eXterminate).
Without the expansions though, Civ5 does have a few holes.