We had great fun with Lode Runner in grade school. I ended up hacking our copy by modifying one of the sectors on disk to let us start at the higher levels, as

We had great fun with Lode Runner in grade school. I ended up hacking our copy by modifying one of the sectors on disk to let us start at the higher levels, as we had at most about an hour over lunch to play the game. I had a handy plastic 6502 reference sheet with all the instructions and details about the CPU on the front and back. Ah, those were the good old days when computers came with an assembly monitor in ROM that you could use for all sorts of crazy things... (edit: this was on an Apple ][e we had in the classroom)