I think the first game I played was this 3D vector game that I played on my family's Performa back maybe 14 years ago. It was called Specter Challenger or something. It was this 3D vector game where you (the green tank, consisting of a couple of connected shapes) had to collect flags, avoid buildings (yellow rectangles) and shoot enemies (red boxes, orange tetrahedrons, etc.) It was so much fun, and even though I only got to play through to about level three or four, I still loved it to death.