This trick works with shots that are left on the screen when you transition. Unfortunely, you can only do this on tutorial screens or in levels with turrets, because once the level is complete, you can't shoot anything, so the way it works is that you must fire with a turret and your ship at the same time, and only one of them must hit the ship to end the level. This way one of the shots will be left on screen when transitioning, and it might hit targets on the new level. On tutorial screens you can freely shoot and progress so you can just shoot and press enter.

There are a few transition shots that save time over the old strategy TAS (which uses one transition shot kind of accidentaly), such as 30-31, 31-32, 32-33 and 33-34, although the most optimal seems to be the 31-32 and 32-33 combo.