Just have a save file with 40 bombs and quit without saving when you run out.
Just keep practicing the ESS position. When you get that down start trying to HESS. If you get a FESS you shielded too late and if you just stand in the bomb you shielded too early. Just keep practicing and you'll get it.
This is the video I made on how the trick works. Details are in the description.
I will do my best, but it may take some time because it is extremely precise.
If it's what I think you're talking about you have to walk off hold left briefly, and then let go while always holding forward you can barely make it. Hope this helped :)
My segmented run of it was nearly perfect and no full game video shows a strat that could save over 2 seconds. If there is a strat I would like to see it so I could improve my times. I think Xcvazer should either post a video or remove the run because there are no known strats to improve that much and he should want to contribute to optimizing the game if he knows a strat
Acceleration does matter in this game. By staying far from a wall while you're falling and accelerating past it without hitting it you save a little bit of time. There are about 5 places you can do it in a run to save around half a second. The timing can be a bit tricky, but if you do it to early you don't lose any time so always go for it.