Aaaaand this is precisely why we don't label things 'final'! =P
I played through the story in Pro mode for my testing, which apparently doesn't show the credits, so I missed that. (Makes sense; you've already seen them if you unlocked Pro mode.)
That actually is the game-over text as found in the original Japanese ROM for that mode when you score badly, and is supposed to represent how poorly Kirby was singing. I'm pretty sure that leaving the original text was an intentional choice by TheDanaAddams and/or Reid.
Exactly this. ^^
Super lucky you caught that weird score display glitch; very specific circumstances like that are precisely why testers are invaluable!
As far as SuperStarFox's question about what's next I can't speak for Dana, but for myself I have another project (Shounen Ninja Sasuke) that stalled out due to a lack of a translator. Check my post history if you want to see where I was at with that. I basically just need to find someone to translate the script. I don't have anything else planned for the moment.
I'd offer to help, but I don't nearly have enough confidence in my Japanese knowledge to translate something like that. Kirby was kind of an easier thing to attempt, since by their nature Kirby games are simple and approachable.
As for what's next for me, I'm not sure! I have about 8 million different projects up in the air that I'd like to be doing, but time and health and tools... and money... are always an issue.
I've been building a hand-wired ZX Spectrum from scratch, but that's stalled until I can afford a part for my ROM programmer; I've been working on custom covers for my collection of cart-based games so I can put them all in clamshell cases; I've got a number of original game projects in various stages; documentary YouTube content; display and accessibility structures that need building; an old, neglected Don't Starve mod that I really want to try and fix and get working again... and goodness knows what else!