My first machine was a Colecovision...similar control schema as the Intellivision...but had a larger library of games that were a lot of fun, if not derivative in some cases. Mousetrap, Ladybug, Qbert and Donkey Kong were the early favorites, followed by Rocky (which had a new and interesting controller requirement), Zaxxon (which was the first flying game I'd ever seen that tried to deal in 3d) and Turbo (even had the steering wheel and pedals). Ahhh...good times.
First PC game I ever played? Strip Poker, on the Commodore 64, on a floppy. Too much info for the cassette tape. How's that for dating? LOL