To my knowledge there are no current autosplitters for this game. GL with your runs regardless!
I think adding Game B as a category would be a good idea to maybe add a fresher way to play the game. As I recall or have noted the RNG in Game B would provide enough difference in the potential of how levels can be beaten and how fast they can be beaten. So there would be enough variety of how stuff must/could be done to warrant it as its own category. These next ones are just potential ideas that I guess could be just summed up as random obligations thrown on by the player, or like category extensions as seen in games like SM64 and odyssey. 1 loop Game A/B glitchless. It is generally known that multiple glitches are patched out in the PRG1 version of the game so this category could be something that PRG1 players would have even ground on, plus it would shake up the strats for a few levels. (I guess you could also just seperate the versions like SM64 does with N64, VC and Emu.) I don't feel the strongest about adding that as a category but I think it would be a neat thing and could spice up the ways to play the game.
Non stop is a gamemode/cheat that when enabled you can collect stars and won't be exited out of the level when you do so. Which is like the scenario you described so that's why people said it may be non-stop.
I might be interested in running I don't know of any arcade emulators though, and plus I thought ladder glitch wasn't possible on arcade but I guess I'm wrong. But yeah that seems kinda interesting to me.
Hello there JAje Nice to see you interested in speedrunning Donkey Kong Jr. Some tips I would have is get really good at mashing left and right to move on vines, also practice and analyze how many times you need to push left or right while climbing. You basically always want to climb up while having both of DK Jr's hands on ropes/vines, and want to always descend with DK Jr on one vine. The top runners use a the PRG0 version of this game because it allows them to do a trick in the third level that skips a portion of the level, you cannot do that trick in any other version but the PRG0 version I believe. Anymore questions? I'd be happy to help!
To add on to JAje Here are my submissions for 1 Loop of both Game A and B of Donkey Kong: Original Edition. Game A. Game B.
Cool, I'm gonna start running that as soon as possible. In fact I am now currently streaming runs of it as I type this.
I would refer you to the guide section located under the leaderboard then watch CaptainSpeedruns Game A loop tutorial video.
There is a vertical line that basically is only a pixel long that you must be at to then tap down and go down the ladder, it is located around halfway through the ladder, so when the front of Mario/Jump man is halfway through the ladder just tap down.
I don't the specifics of why it works but I can tell you how to do it if you want.
For 70 star do the same thing but in normal Lakitu cam, and once again up the stairs and then don't go down to the bottom juts hold down for a bit and then do the BLJ, sometimes I just get caught on those stairs as well but you should just keep trying it's not that much of a problem for me at least.
You don't have to do a certain route for a category but there are certain checkpoints/guidelines you have to do in categories, like you can't SBLJ in 16 star you have to use Mips.
If you are new you should try those beginner and/or advanced to have a good basis to go off of, and start watching other speedrunners, near/above the skill level you might be at, and figure out what tricks you can do at that time and optimize your route to your liking.
For the 50 star door I recommend using Mario Cam zoomed out. Hold directly up for a bit then straight down to the bottom of the stairs, start you BLJ and start mashing A when Mario is about to hit the stairs and if you don't pick up speed immediately keep BLJ'ing holding back and wait to start mashing A again until Mario is about to hit the stairs once more. Then just repeat that.