Apparently it's Sega model2 discoveries day. After finding some code in Sonic the Fighters that literally was useless, I felt it might be an engine leftover, and sure enough, the code actually did something in Fighting Vipers. Alternate Intro (Arcade Edition): The game must have 20,000 "VS" plays. 1 vs play counts as a player versus player match. If this condition is met and if P1 Start + P2 Start are held just before the attract mode ends and the first CPU vs CPU battle begins without any credits inserted, the player will be treated to an alternate attract intro featuring a very playful Honey instead of the Fighting Vipers logo. Also there are subtle differences to the attract into as a whole when this "cheat" is active. As @TrackerTD pointed out, this can be done in the 2012 XBL/PSN port simply by pressing P1 Up before the second attract screen, and the achievement "Sweet Tooth" is also unlocked by doing so. EDIT: Aww, don't have twenty thousand plays on your Fighting Vipers board? Don't worry, if you have a meager 15,000+ versus matches played, holding UP+START will start "Random Mode", which as the name implies allows you to play various, non-linear, characters in story mode instead of the same order of characters each time! EDIT: Someone on Twitter is disputing that it takes 15,000+ matches to activate random mode, as they said they have activated it on their cabinet and were absolutely sure it never had 15,000 plays on it. I will look into this, but that is kind of what the code says. Perhaps they had a different revision? EDIT2: They were right. holding UP+START to enter the character select screen will activate RANDOM MODE no mater how many plays the cabinet has, which makes me wonder what I am looking at in the code.