Speed: Fine for me. Seems very close to original Pac Man speed, at least while the player is running.
High score table: I have been begging Mark Lord to think about adding disk-writing capability to hijack. He has a scheme in mind where Hijack could take a few sectors of the disk and write to them, even though the disks aren't mounted r/w. I have a few uses in mind for my software, and the high score table is yet another good reason to have such a facility. However, Mark is enjoying his summer like the rest of us, so we might not get such a feature for a while. I would shy away from any high score feature which needs to mount the drives rw, I wouldn't want that at all.
Great job with this one, it's really a fun game and I look forward to a release with source code. As someone else who was slow in releasing the source to my software, I say take your time and clean it up... If I had released my first draft code, it would have been worthless. Great stuff.