Chainsaw Joe.
A game I was fully convinced I could program in BASIC on the ZX Spectrum, when I was about 12. It was about a leather-clad Mad-Max-alike (see Mike Jones, my previous post on this thread) who carried a chainsaw through the post-nuclear wilderness, killing punks and tracking down somebody called the Mutant (thanks, City of the Damned). It would have been something like Green Beret with a cool storyline if I had had the programming abilities I believed I had. I'd really, really overestimated myself there though.
On the plus side, my friend and me told a guy in class we'd lend him scrolling shoot-em-up Spy Hunter, and proceeded to programme our own version of it. We did the loading picture and made a text-only version of the game, in which every possible outcome resulted in the player's horrific and graphically-described death ('You are found the next day with your head open and your brains dripping down a tree' is the only bit I can remember).
Anyway we swapped it with him for a proper game (which we copied and swapped back). i don't think we ever told him - he thought the text bit was a prelude to the action arcade bit. Sorry, Keith