On puzzle 1422, combining the "X-ray tunnel for ligand" from the regular view options with "Show Isosurface" from the "Small-Molecule View Options" produces an interesting effect.

At one angle, the X-ray tunnel seems to function as intended, providing a view of the ligand:

If the protein is rotated slightly, the isosurface obscures the tunnel:

The "Show Isosurface" for this puzzle is not the one from the normal view options. For this version of Show Isosurface, in the selection interface, select the ligand, then click the "Ligand Properties" icon or use the "V" shortcut. The "Small-Molecule View Options" dialog is displayed. Many of the options will crash the client, but "Show Isosurface", and even has an adjustable cutoff.

Based on a previous feedback, the ligand tools were enabled by accident on this puzzle. The adjustable isosurface seems like a new feature, however, and might even be useful in some cases.