Hi, first time participating in this jam. I'm looking to give myself an extra limitation for this jam, being that I make the whole thing from scratch in C#. As such, that would mean I'd be unable to export to a web build. Is this allowed? Thanks

Yes, as long as it's playable, no restrictions. Someone in the past jam even made theirs work on an N64 emulator.  Looking forward to see what you come up with.