I actually played this game once as a kid, and now I have played it many times on MAME. The game is hard. I mean super hard. Someone is listed with a high score of 781k. I don't know how on earth he pulled that off. I got to 250k with no rematches, and that was a minor miracle.
I have been reading up on this, and apparently I guess there is only 20 rounds in the game. No one but this one guy has ever reached the ending.
I wonder what the ending looks like? My guess is you would need save states along with invincibility in order to reach it. I can't get past round 7 with rematches or no rematches. That's the second masked x who happens to be bald bull.
In fact I don't think anyone besides that one guy has passed round 10 in this game.
I definitely think in regards to killscreens or end of games in regards to Nintendo Arcade games this is one under rated killscreen/end of game.