Great job, especially the Z sentence, which is probably the most difficult to integrate.

Lollygagging is a great US word that I haven’t come across before – now filed away for future use.

Very vivid, engaging little scene and the limitation on sentence structure isn’t really very noticeable to the reader – so well done for constructing something that still flows quite naturally despite the constraints. Your X sentence is unusual and interesting (through it tripped me up a couple of times on the first read).

Skyrim appears to have catapulted that word (“lollygagging”) into popular langauge.

This is really great, especially since the limitation isn’t easily discernible (as Jon points out).

Skyrim? Of course: the popular action role-playing video game (thank goodness for Wikipedia).

Re-reading this, I think you have a misplaced apostrophe in G.I.’s, THX.