itch.io

Have you read the notes nearby? They both give pretty solid hints at the answer.

Basically, the codes are a letter-to-number cipher, where A=1, B=2, C=3, etc. etc. etc.

Here's the solution, but I'll put it in strike-through so it's easier to skim over if you don't want to know the answer: Red: 1854  Blue: 212215