Just replayed the first one for the fourth time last night, and today there's a sequel out I didn't even know was in the works. Have found something strange, though. Injection 6's automation upgrade is cheaper than the challenge itself...so I should be able to just buy the automation and do a SPU reset and complete the challenge without having actually completed the challenge legitimately? Doesn't seem intentional. Interesting game so far, though.
Edit: Oh, also, the description for the tree is misleading. It should say "Branches with no children", not parents.