I suggest removing the infinite ammo category, since it did not make a difference in the runs.

I found, that after doing the fast method at the very top, I could dash left and then right and make it through the gap.

here is a video of me doing it:

Im not sure if it is faster, but the dust cloud animation in my test is on Frame 1, when doing my new method and doing the normal speedrun method the animation is on frame 6 or so. https://imgur.com/a/GAgdctR

since it its pretty precise and only saves a few millieseconds it not useful in full game runs.

This happened to me a few times, but i have not seen it on here so here you go.

When I dash to the right as early as possible tow stones break at the same time. Video:

Also Im using Duke Dashington Remasted on ios and have not testes it on other pattforms.

If u jump right at the beginning and dash to the right then ur ur a tiny bit higher than the starting point. Because of that u can spam dash right at the wall and damage it 2 times. After that u dash ontop a pillor and derstroy the wall. This trick saves u about 1-2 sec. And its hard to get. Good luck!

If you keep standing under the first block and time it so when the stone wall breakes you dash to the left than you will dash throu the block, whitch is fallen from the top against the next wall. I was not able to do this glitch at the second wall, but it saves a half - 1 second. Its perciced but with practise you can do it the most of the time. Good luck Edit: its also possible in lvl. 23