Very nice looking puzzle Justin.
Maybe it'll reach mass production like the 3x3x1 hearts did
Considering they did that without asking him, or giving him credit, that might not be the best thing to wish for.
It gets a little awkward because they're using a KO design idea from one person, applied to a KO of a different person's mechanism. I wouldn't want a name credit on a QJ Heart which is a KO of Katsuhiko's mech. I'm pretty sure they could have made a visually identical puzzle by using a 2x2x1 mech with two 1x2 extensions at right angles to each other - it would just scramble differently.
I must be missing something obvious, but I can't figure out how this mod is done. The 2 rounded faces are on adjacent faces of the 2x2x2, and they turn, and I don't think the Rubik's Tower can be put into a state that allows that. I've only been able to turn the outer faces on the 2x2x4 when it's shape is restored, i.e. when the outer faces are on opposite sides of the 2x2x2.
You haven't missed anything obvious. I had to modify two of the pieces to take 2x2x1 extensions at right angles to each other (like a Cross Cube). Two other pieces had their 2x2x1 slots blanked off. I could have built it on a mini ES or Pocket cube, but with a 2x2x4, most of the work is already done - I'm lazy