People talk about how the Afterblank series are a spiritual successor to X-COM. This is...somewhat inaccurate, when speaking of Aftermath. Allow me to explain.

Aftermath contains quite a few X-COM-like elements like interceptions, geoscape/tactical, and the alien invasion premise. However Aftermath plays fundementally differently. Your interceptors, for example, are semi-disposable. There's no money-management aspect as you represent more or less the last of humanity under arms. Weapons selection for your troops is much more varied, though you'll find that this doesn't add terribly much to the game.

Most of all, the tactics are very different and somewhat dumbed-down. Playing Aftermath the same way you played Enemy Unknown or Terror From The Deep is possible against the lesser transgenant enemies or in the late game when you're packing gatlings and enhanced plasma rifles and god knows what else. But usually, you will find that the advantages of concentrating your team together outweigh the advantages of dispersing them; there are no hostiles with grenades in Aftermath, and you will need the concentrated firepower against Reticulans for most of the game, outweighing the dangers.

Aftermath is much more forgiving than any of the X-Com games as well. You can make mistakes. You'll lose at least fifty aircraft a playthrough and more likely a hundred plus, something impossible in an X-Com game. There's actually a lot less scope for tactical engagements in the game, and the only opponents it would matter against, the Reticulans, it really makes little difference except for remembering to put the guy with the CAWS or flamethrower on point.

If Enemy Unknown and Terror From the Deep were too tough for you, Aftermath might meet your needs. Apocalypse is a closer cousin to Aftermath, and so those who enjoyed it might also enjoy Aftermath despite its major departures from any of its cousins. Overall though, I find Aftermath difficult to recommend strongly; it's eminently playable and it's well-made, but it's just not as engrossing as the tactical X-Com games were, primarily because it lacks their incentives to force you to think.