I guess we can add Fig. 8 to the list of games I kind of rule at. My current high score is 9,140,953, and I've figured out a path that will work to get through the entire game with a single purple line behind you, which should produce a score in the hundreds of millions, if not billions. My path is based on the two videos below, with the following changes made to that player's route (the videos aren't mine):

Part 1:

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Part 2:

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In Part 1, at 5:07 head to the right, and then go down between the rocks toward the right, rather than ducking around the line of tracks.

In Part 1, at 5:49 go to the left of the observatory, rather than the right.

In Part 2, at 0:09 go to the left of that bar, between the top left corner of the bar and the F that's next to it.

The hardest parts of this path are getting between the houses at 2:55 in part 1, my first and third edits as listed above, and getting under the text at 0:59 of part 2. The rest is just memorization and practice.

Also, and this video is mine, here's the fastest route (including annotations) to a 500x multiplier, and the Trailblazer medal:

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