The original UFO: Enemy Unknown was great... and was based on the pure classic on Commodore Amiga and Sinclar Spectrum: Laser Squad.
UFO had a number of offspring, with XCOM being the main branch that went forward. IMHO.. this branch got weaker with every release...
Turn based strategy ftw... lost hours on UFO.. but it got impossibly hard really quickly. Just as you made progress, the aliens would turn up, kill your squad and take over their minds!
