this may work with all bombing missions, but the bombing mission at abyssal shelf is always annoying for me because sometimes i have to go back
remember the mission where you have to bomb 20 peons, 5 cannons and 5 overseers?
If you hotkey a bomb it is possible to throw up to 3 bombs at once if you spam the button while clicking, it is hard to get the bombs to land far apart from each other but it is very possible and makes getting all of those kills a bit easier