Took a bit more than an hour, but I did manage to push GB Rober's speedrun world record down to 23 minutes. The run also has a fairly funny and thankfully inconsequential "my planet needs me" bug somewhere towards the end. Overall I'm fairly happy with it, but I also know how much more you could squeeze out of this game, if someone would just have the patience to work on it, which I probably don't have.
Anyway, if you're interested in seeing what's theoreticall possible in GB Rober, if you ever wanted to go fast in it, you can watch the run on Youtube: