I've amended the following to the rules for submitted runs:
- Game difficulty settings: Easy.
The reason is simple: there is no way for moderators to clearly verify how one's MAME emulator / arcade machine DIP switches are set unless the runner chooses to either show his MAME config, or show the physical DIP switches on the arcade booth. The first option can be annoying, especially if you reset a lot, and the second option is just plain ridiculous.
Furthermore, additional investigation on the actual WR (by wpginterceptor as of September 19th 2017) indicate that it's been done on easy difficulty. On normal difficulty, Insane Warrior takes 9 shoulder blocks before he will take two piledrivers in a row. No RNG of any kind influences this as it is directly related to the damage that has been dealt to him. Now, the current WR achieves this after only 7 shoulder blocks, which is exactly how many it takes on easy before he'll take two piledrivers in a row. The next 4 characters take respectively 8, 9, 9 and 10 shoulder blocks on wpginterceptor's run (the exact same it takes on easy), whereas on normal difficulty, the next 4 should take 10, 10, 11, and 11 shoulderblocks. This information can be tested AND counter-verified on any MAME / Mat Mania arcade machine by changing the proper DIP switch settings. Long story short: the victory time was shorter because the difficulty level was lower.
Now since no previous rule was set with regards to difficulty at that point in time, the WR stands as is. It wouldn't be right to invalidate it because of an omission on my part with regards to the rules. However, to level the playing field for everyone, the rules now state that the game's difficulty should be set to easy. Setting it higher will simply be detrimental to the runner.
If there is an interest in making categories for the other difficulty levels, this will be considered. However, this will require the runner to show his difficulty settings before starting the run, which can be a bother, especially if one ends up playing on the actual original hardware. But we'll cross that bridge **if** we ever get to it.