A friend of mine in my CS class wrote a SUVAT simulator, except he branded it as a revision tool. It would ask a question, the user would work it out and enter their answer, then the simulator would run to show them what would actually happen in that situation. He got a very good mark, I think 74/75 raw.
As other people have said though, the vast majority of the marks come from your documentation - follow the headings in the PDF exactly (where applicable) and you'll be alright. The high-scoring projects in my class all had 200+ pages of documentation. The one person who got full marks had over 500 pages.