The game that makes hardcore gamers cry.
The game is insanely challenging at all difficulty levels, has many moments where you'll need a clean pair of underwear afterwards, and combines strategic thinking with tactics. Your overall progress in the game is measured by how well you complete missions, which can make or break your game. I think what I like best about this game is that the gameplay stands the test of time; it's still a very good design after all these years.
The only complaint one might have about the game is that the game is difficult. Even on easy it is possible to lose even when you know what you are doing. On the highest difficulties, I've managed to lose in one in-game month. I've heard rumors of somebody building a mod for it that makes it even more difficult, and that's not something I wish to imagine.
The Bottom Line
The game is a take on the classic alien invasion scenarios one encounters in pulp fiction and Sci-Fi B movies. You've got several races and species of alien creatures. There's your typical little green men, your big-headed alien psychics, mutated earth creatures, the obligatory reference to Alien, and nasty cyborgs. The game consists of the Geoscape where you manage your bases, personnel, equipment requisitions, research, and of course send out aircraft to intercept UFOs. The other half of the game is spent in the tactical combat mode, where you actually kill the invaders. The game's plot progresses as you successfully complete missions and gain new items to research, all contained helpfully within the UFOpaedia. At first the conflict is rather one-sided, but as you research, you actually start having competent soldiers as well as the advanced equipment to fight the aliens. Of course, the aliens do not sit on their duffs; they respond to your success in a variety of ways.