That sucks but nothing can be done about it i guess. Maybe some other dude will try this game and get it finished. Good luck!
I decided to play Indy Infernal Machine for N64 today and found a shortcut in level 1 that this speedrun does not use:
Skips a short hop, arm-sidle and climb-up. If you move/aim a bit more to the right before jumping you can avoid having to scoot rightwards before climbing up. It's hard to do without stopping and aiming briefly, at least on N64. I know the PC version is a bit different (noticed the run does some tricks that are definitely impossible on N64) so this trick may be N64-only and/or already known about but I have no idea.
Skips a short hop, arm-sidle and climb-up. If you move/aim a bit more to the right before jumping you can avoid having to scoot rightwards before climbing up. It's hard to do without stopping and aiming briefly, at least on N64. I know the PC version is a bit different (noticed the run does some tricks that are definitely impossible on N64) so this trick may be N64-only and/or already known about but I have no idea.