Spelunking really deceived me for awhile. Tried all the wrong approaches first. Nice one. More tries than the Machine for me. Nice variation to screw over anyone that did the other one the other way. i.e. me. Exceedingly logical. Enjoyably tricky. Beautifully designed.
The **** is up with those unused spaces though? Unique "unlock" puzzle. Got it immediately but was 2 off. Really easy to miss that one. Damn. There are a couple unique 56 paths and the final cuts on the correct right are tricky and clean.