I am perfectly aware of the fact that in the original arcade version it is possible to throw the pump through thin walls, but personally I have always considered this behavior a sort of bug or something not perfectly defined, and therefore I decided to fix it. Regarding the general difficulty of the game, I can assure you that the arcade version remains far more difficult. If you had the opportunity to try it with MAME, you would realize it.
Anyway, thanks for liking the game and letting me know.