“Base code and personal code libraries are allowed, but should be declared and shared with the community prior to beginning your entry. To do this, make a blog post.”

Based on this I believe the platformer kit would be allowed, as long as it is declared and linked before the compo. As long as you are not dead set on getting your entry judged, it might be a good idea to go ahead with the platformer kit as you can relegated yourself to jam at a later point. There’s no shame in doing so, or there shouldn’t be. I made the mistake of entering my first LD without a good codebase and consequently came out of it with an engine proof-of-concept in the jam. As long as you submit something you can still judge other games and people will still give you feedback even on a jam game.

Can we have an official ruling on this though? It’s something that should really be clarified in the rules.

If you modify it, you must do it during the compo, OR release your modifications before it starts.

However if it includes gameplay code (monsters behaviour or stuff like that), I don’t think you’re allowed to use that.

Offtopic: Is it true that LD21 is sometime in August or so?

What you’re describing sounds more like a mod than a game from scratch, so I suspect it wouldn’t qualify for the contest. But I guess you could enter it in the Jam!

Of course, by the time LD21 kicks off, you’ll have had an extra few months to practice, so you may feel ready to tackle it. I’ve certainly learned a lot about Unity from this Dare…