So far, 88 entries have been submitted to this jam and there's a good few hours left. But I believe the amount of games which get continuation on day 2 will be a lot less, maybe 2/3 of them or something. Later days likely will be more stable as there's less original games to continue from. My guess is that on day 6 all games will have roots in 1/3 of the original day 1 pool.
I hope users of all engines will have some entries to work with even on later days - there needs to be at least 6 devs who use the same engine, and that's in the ideal case where everyday somebody is available to continue, but each in succession. Unity games will definitely be in final day, and Godot seems to have strong support too, but I'm afraid for some frameworks not having enough devs joined...