WTB Cdn sealed black boxes, sealed Cdn first party titles. I.e. the "mattel" Cdn boxes with both french and english. Mainly black boxes, zelda, link, and tyson, but let me know what you have. I am interested in anything I don't already have!
I went back through all of the available Semrad columns from October '87 to July '88, and here are all the Return of Donkey Kong references:
Jan. 16, 1988 (CES Report, listing all the upcoming NES titles):
"Nintendo - R.C. Pro-Am, Ice Hockey, Zelda II: The Adventure of Link, Return of Donkey Kong, Super Mario Bros. 2"
Feb. 27, 1988:
"The latest schedule for the new Nintendo games is: Ice Hockey and Pro-Am Racing - early March. Zelda II and Super Mario Bros. 2 - early June. The Return of Donkey Kong - sometime in the second half of 1988. Dragon Warrior - 1989. As you can see, everything got pushed back by quite a few months."
May 7, 1988 (A themed column about game sequels. Most interesting text is bolded):
"For Nintendo, there is Super Mario Bros. 2, Zelda II, The Return of Donkey Kong. For Sega, Zillion 2, Fantasy Zone 3, Alex Kid 2. The trend is good and bad. It's good because quest games like Gauntlet are very popular, few in quantity, and in demand. On the other hand, sequels are bad because companies get into the rerun mentality; BY JUST CHANGING A FEW CHARACTERS AND WEAPONS THEY CAN MAKE ANOTHER GAME. TITLES LIKE THE RETURN OF DONKEY KONG JUST AREN'T NEEDED. Sequels also inhibit new and innovative software. A company doesn't have to take a chance on possibly losing money on a new idea when when it is guaranteed some profit on an older title."
In his Summer CES report from June, '88 he lists Nintendo's upcoming titles, and Return of Donkey Kong was not among them. I don't believe he ever mentioned the game again.
So, after reviewing all of the available facts here, I've come up with a theory. Rather than being some mysterious original game, or just a different title for what would become Donkey Kong Classics, it was actually a slightly altered and enhanced version of the original Donkey Kong.
My thought process here goes something like this: In 1988, Nintendo released a few slightly altered or enhanced versions of early Famicom carts as FDS titles. There was Ice Climber (closer to the arcade version), Vs. Excite Bike, and most notably Kaettekita Mario Bros. (an edited version of which was eventually released in Europe in the early 90s, I believe). I'd even go so far as to speculate that the ultra-rare New Clu Clu Land, released as a blink-and-you'll-miss-it afterthought in 1992 when the FDS was as good as dead, was probably also designed during this time period but then delayed for unknown reasons. You'd imagine that Nintendo would also have considered one of their most venerable and popular franchises, Donkey Kong, for this special treatment. But perhaps this one just didn't quite cut it for whatever reason, even with some minor control tweaks, the ability to control Donkey Kong and throw barrels at Mario, etc. Maybe the few members of the gaming press who saw it, and ultimately Nintendo's own quality control people, gave it the big thumbs down. After all this, NOA might still have wanted to wring the last few dollars they could out of the aging franchise, so they just went ahead and released Donkey Kong Classics instead, justified by the fact that they were offering "two games for the price of one" and that the original titles had been unavailable for some time at that point. Nintendo did something similar in Japan (where the silver box re-releases of early games like DK were starting to go out of print and becoming difficult to find), releasing unaltered versions of both DK and DK Jr. as budget priced disk writer titles in 1988. This is all conjecture, of course, and I realize there are a lot of moving parts here. But, if you start to put them all together, a somewhat plausible explanation starts to emerge. In any case, I'll defer to your opinion on this matter, as I'm sure you've spent much more time researching the history of this title than I have.