In a postmortem panel at GDC on the development of last year's sucessful DKCR, Retro revealed the difficulties of making the side-scroller. The team attempted to adapt the Metroid Prime morph ball camera to the side-scrolling, but found it unable to handle the quick and complex movements of the DK characters -- especially once Tanabe insisted that two-player simultaneous play be added.
There are over 2000 animations for the player character, a number inflated by the second character -- and by the late-stage suggestion from Shigeru Miyamoto that Donkey Kong be able to blow on background items to reveal secrets. Miyamoto was testing the game, running back and forth for about ten minutes, when he declared that Donkey Kong appeared to be exhaling when he turned around. And then, he said that "it might be fun to make Donkey Kong blow on things," causing extensive damage to Retro's metaphorical tea table.
And the Super Guide -- "oh, jeez," one of the team exclaimed when that subject came up. It turns out that Retro had to rewrite the engine to make it deterministic -- make it that all the inputs would result in the same output every time, essentially eliminating randomness. This turned out to be a boon, however, as the same mechanic that allowed the team to record playthroughs also made it easy to reproduce bugs in testing.
Retro ended its panel by joking that it would like to refresh the Doki Doki Panic (Super Mario Bros. 2) series next, along with making a "Pokemon Prime." "We've been looking at Tingle a lot," as well.