After many years of trying all kinds of squad-based strategy games I always come back to Laser Squad. To me it's simply never been beaten for immediacy, ease of interface and replayability. I actually have fun playing it, something that often seems lacking in other entries in the genre. There seems to be a line of complexity over which I lose interest, but Laser Squad hits it just right. I want to choose what equipment to take, and that's it. Straight into the action.
Even though there are only 6 missions they vary generously in objectives and environments, and as with any good strategy game they really come alive in multiplayer. Having said that, I never, ever tire of blowing apart the home of Sterner Regnix, or making my way cautiously through the Moonbase. Even against the computer Laser Squad is very entertaining and rewarding.
Julian Gollop has expanded his series in various directions, and Laser Squad is still going strong today, albeit in a substantially different arena. None of them have managed to top the purity of this classic.