The Retron 5 did indeed release, but from the sounds of it, Hyperkin didn't release nearly enough to meet preorders. I preordered through a local store and I'm still awaiting fulfillment on the gray console. The black console won't be released until September, maybe..but that was only announced within the last few weeks, I think. Maybe around the time they raised the price by $40?
It can kinda be considered vapourware, though, maybe, because I think the Retron 4 that was never released just sort of morphed into the Retron 5 after that one was delayed for nearly a year, too.
No Mercy is one of favorite games of all time. The controls are among the best ever made. So simple to learn, but still, masterable. 4 way matches take forever, and Ladder Matches can be better than a real wrestling match. No joke.