I know the Speedrun method to locking him in the corner, but I always struggle to defeat him the proper way. In other videos I see that it's easy for them to defeat him, but when I try, I can't reach him or he always manages to escape from me. Eventually I do defeat him, but I don't know why sometimes the game allows me to get the hit and sometimes not. I know that I can sort of slow him down with the elevator's engine, but it's still very luck-based.

So what do others see and I don't?

Brandon, he was asking how to defeat him the normal way, not the speedrun strat. The normal way would be to run backwards so zurg chases you, then turn around and spin jump up. Or just charge a full spin and hope you get a little lucky if he runs into you or something like that.