there's all sorts of differences between japan/usa/world versions,
commando by capcom comes to mind.
for the world version (plus the japan version), as you run up the screen of the first level, look at the palm trees and you will notice that often large parts of their graphics disappear.
the US version is ok though, it doesnt happen in that version. i assume the code was altered.
it's not a mame bug btw, it happens on the real pcb as far as i can see (eg. here's the japan pcb, watch the palm trees..

)