Per the inevitable, the guy is better than me at Spelunky, and in particular, at killing the shopkeeper.
There is a completely non-timing-based attack you can do with some shops, though, which occurred to me today. If the ceiling above a shop is thin enough, you can blow it up with one bomb, then keep on tossing bombs down from a place too high for the shopkeeper to jump and shoot at. (You use a lot of bombs this way, though.)
The shop I happened to attack had a bomb box that miraculously did not get hit by one of my bombs. So, I had a ton of bombs for the rest of World 1.
This allowed me to bomb the floor Quillback was on, and he kept rolling to lower surfaces, which I also bombed. Eventually, he was at the bottom of the level.
I forgot that there is a shopkeeper in 1-4, and he was camping out near the exit to get me, as angry shopkeepers do. He actually killed Quillback for me.
Then, he got himself stuck in a web. He could still shoot at me, though, so I had to lay low, then toss one more bomb at him. Though it now occurs to me, I could have used my timed jump to just run out the exit.
Then, I went to Volcana and fell in some lava.