Rezon is a fun little shooter with a couple interesting leftovers (maybe one is an easter egg?). Sadly, neither finds are as amazing as the game's ending.
It's a basic input test and what appears to be tracking for game continues and finishes and total plays. It may be a leftover from a location test. It doesn't seem to actually track anything, though, from the quick test I gave it. Which makes it... pretty useless!
To access it, hold P2 Start + P2 Left + P2 Down + P1 Button 1 while the machine starts. You'll need to hold it through the RAM test. When it appears, you can let go of all buttons except P1 Button 1; letting it go will exit the menu.
ASCII art logo
And at 0xD6B0 in the data, we have...
ZZZZZZZZZ RRRRRRR EEEEEEE Z OOOOO N N R R E Z O O NN N R R E Z O O N N N RRRRRRR EEEEEE Z O O N N N R R E Z O O N N N R R E Z O O N NN R RR EEEEEEE Z OOOOO N N ZZZZZZZZZ
ASCII art! Is it an easter egg, or was it actually used in the code? Each line is a fixed width, separated by 0x00's, which isn't either of the usual newline characters. That makes me think it could have been used by the code at one time, maybe as a temporary title screen. It doesn't seem to be referenced anywhere anymore though, so who knows. It's interesting at least.