Aha! You also seem to have changed something that always bothered me - I now start with my weapon equipped instead of having to equip it manually every time.
I've just been playing some more and I realised I haven't seen stairs up to the surface in the newest version(s). Have you removed that whole surface area?
Any chance you could provide the source, or compile a 64-bit version?
I can, but for Windows or Linux? I thought you can always run a 32-bit program on a 64-bit system?