missingno.sav Game Boy reversing challenge writeup
On March 31st 2017, TheZZAZZGlitch released his April Fools 2017 event.
The event being a crafted save file for Pokémon Blue, it being a small game where you need to use memory patching or debugging techniques to beat it.
After you beat the game, a password is generated which allowed you to submit your score to the event website.
The best score (naturally, that score is
31337) can only be obtained by either patching the key-generation routine ("crackme"), or making your own keygen ("keygenme").
I, personally, did the latter.