After intial dicussion with other moderator and runners, it was agreed, that Switch runs should be put into separate category. The main reason behind this settlement is how Switch handles left+right and up+down inputs. For proper emulation (present in FCEUX, NEStopia etc.), which disables L+R, U+D inputs, there should be no input registered, when both opposite direction are pressed.

However, that's not the case for Switch, where if you press right, while still holding left, then the right input overwrites the left input. What's more, in case of DK, this Switch behaviour is exactly the same as allowing L+R,U+D on different emulators. That makes rivet skips in level 3 much easier to execute, since you don't have to wiggle between left and right frame perfectly without losing any frame between inputs, instead, you can just start holding opposite direction without releasing the other one. Additionally, it makes ladder zips much more possible, where normally, you have to wiggle up and down frame perfectly.

Due to those factors, we are leaning towards separation of Switch, unless there is a way to alter this behaviour to proper one, where no inputs are registered with both opposite direction pressed. This thread will be left here for few days at least, before the change is introduced to make more people aware of it and see their point of view.

I agree that the method used to resolve opposing directions on the Switch version provides an unfair advantage. However, it is worth mentioning that the Switch is not alone in enabling this advantage.

Some unofficial emulators, such as puNES and ares, resolve opposing directions by registering the last input pressed instead of cancelling both inputs, which similarly allows for switching directions frame perfectly. Like with Switch, one can hold left and then simply press right frame perfectly to perform a rivet trick. Even if these emulators were disallowed, one may use an external program such as hitboxer to silently employ last input handling on an operating system level. Mods wouldn't be able to detect this without requiring runners to show the current programs open.

With that being said, keyboard and unofficial emulation can offer a big advantage for this game if left unchecked. The SMB1 mod team had to discuss this issue when it was made aware to the community and while the consensus was to only allow emulators that cancel opposing directions and disallow external programs that circumvent this behavior, not much can be done to ensure people aren't cheating the system just short of heightened proof standards.

I'm not one to say whether runs performed on an emulator should also be split off or not, but this is an underdiscussed issue that could have serious ramifications on the integrity of speedruns for this game and other NES titles.

There is no doubt, that emulator and keybaord itself give already at least some consistency advantage against runners on real hardware with original controllers due to many factors like how you can setup your inputs, how they work etc, however it is usually widely accepted, that they can coexist under the same category with some exceptions like Kung Fu. It's a very thin line, what crosses the boarder of acceptance and what not. For many people, overwriting opposite direction is allowing that one step too far, since it's making execution especially in games like DK much easier and it was also standard rule almost everywhere, that L+R should not be accepted, because it diverges too much ftom how inputs are read on real hardware, thus the decision for separation was brought up.

As for cheating, it is true, that we have to relay on some level of trust from runners, especially on emulators, however it is not that much harder to cheat on real hardware to some extent e.g. connect 3rd party controllers, which allow L+R or even connect Playstation or Xbox controller with proper device, so you can very easily press one direction with dpad and the oppostie one with analoge stick.

In the end, although many people put serious time and effort into achieving their speedrunning goals, I still see it as cool hobby with a lot of satisfaction and entertainment usually without any price money involved. If we would like to be 100% professional, then we would have to not only separate emulators from original hardware on NES, but also force everyone to have camera on their controller, whole setup, desktops etc to be as much certain as possible, that no one smart enough got away with cheating. However, as said, it should be first of all, focused on having fun with as many people involved as possible. At least, I would like speedruncom to stay on that side , having some set of a little lenient rules, which runners abide as long as most people agree to follow that way.