I have not enjoyed strategy game as much as this one from (he he) Civ 2. Firaxis really delivers here.
Those who criticizes things like small squad size - it is not. 6 is enough, even more than enough. You do not gain anything strategically increasing the size, but making game more boring with unnecessary micromanagement. The criticism comes only from those who played the previous XCOM games, and just used to some things happening in some way. 6 is much better, in fact, while 5 could be as good, 7 would be definitely too much. You have only 4 fundamental classes to play with, so when you have 6, you already have 2 classes having more than one representative on the field (though you can modify them to have slightly different roles. Like one of my sniper was OK at close combats, and another was not at all, but could use indirect vision to shoot from really far distances.)
There are some arias that can be, no, not improved, but further developed. I wold like to see more options accessible in weapons, because so far, it is not an option exactly, you simply put the best armor, the best rifle, and so on (or nearly so).
The air combat is really bad, does not contribute much into the game. I wish they either removed it or over-thought it completely. But it is very minor portion of the game, so, whatever.
Any way, the story is good, the game-play is addictive, and the game is great. It is so great that I have decided to write review, which I did not do in years. Do yourself a favor - buy it, especially since you likely can find it on sale.