Yep I couldn't let Cyberzone get just one vote. Also, thanks to this poll, I've learnt that Bug Blaster was the author's precursor to it*.
1 - Cyber Zone. Bonkers. Hard to imagine on another system. Quite good fun.
2 - Halls of the things. I never got into this, but I know enough about it to feel it should be 'up there'.
I nearly put "Wooluf" at #3, but I can only choose 1 & 2 really. Hand on heart, I'm not able to say this UDG sheep herding game beats Rommel's Revenge or the two text adventures.
*actually both 1983, but it's a fair guess to say that BB came first.