They got rid of the biggest thing I disliked about Going Commando - space combat.
There is actually some challenge to UYA, which went absent in GC, even though it only took me two tries to beat the end boss.
Unfortunately, finding the Platinum Bolts don't gain you anything useful, which is doubly detractive for me since almost all the PBs are pretty easy to find, unlike in the previous two R&Cs.
The one major technical problem I found with UYA is found in the Sewers where the slime-like beings would disappear into the walls and still attack you, much like the Y.E.T.I.s disappearing into the snowbanks in GC.
