When I got my C64, I started the project Overload Revival. All I had was a damaged printout of atrocious BASIC code. It has no spacing, the variables have names like Q% or K, it creatively uses GOTO, and of course there was no internet to look up anything. My C64 version took time to develop, but eventually worked and introduced an important factor: colour! It looked much better than the original. I lost the sound effects, though, apart from a few clicks. Never got into programming the sound chip.