It's meant for game jam events, where people are challenged in making all sorts of games, or ones of their choosing, in short time constraints. Two weeks works for this event but I'm not sure who would try using a new development tool last minute. I think most of the challenges are coding from scratch anyways.

I don't know anything about Facebook owning Opera. I think they wanted to buy them nearly a decade ago but it didn't go through.

Very ;) Give it a try =)