I do think this is a very interesting mechanic, but sadly, I ran into too many bugs to get very far : / (Especially because I'm my bad-at-platformers self)
In case any of them help if you end up looking for them: for one, it seemed that one of the foxes being killed by a frog didn't stop my gameplay; for another, it seemed that the screen would only ever go to the right, and would eventually just... be way to the right of where the characters were. That was the one that lost me, because I was unable to make it so my characters were still on-screen for me to play with them for very long. At one point I was able to just keep hitting jump and side, and it looked like an auto-scroller (but without the characters) and I didn't lose until somewhere halfway through the level just by virtue of ... well, I'm not really sure what happened since neither fox had been on-screen for a bit by that point, but I surmise my remaining fox finally ran into a hazard that it could not surpass. It did seem as though the foxes could infinitely keep jumping.
Sorry that came off so harshly! T_T I really would be interested to see how this played if the game would stay in its screen. Either way congratulations on putting it together, it's certainly more than I could do!! Thanks for the fun experience ^_^ Cheers.