Today an entry from Sillyventure 2017 was finally released. When I saw it on the stream I was pretty sure this could have been done in rb+. And it is actually written in it!
I'm really glad people find rb+ useful and make things in it, especially when they come out of the blue with a release!
Will update this post with a video when there's one available, for now head over to pouet.net and grab the rom yourself!