amogus, i only want to know
That would depend on whether or not it is a new project written while this jam/compo is running.
Here's the relevant rule:
https://gbdev.io/gbcompo21/#rules
17. Your work must be new and original. You cannot enter with something you were already working on before the start of the jam. The majority of work should be done during the jam. If in doubt, please ask us before proceeding.
Examples of things that are allowed:
Examples of things that are not allowed: