Here is a preview of the new setup where you go directly from one boss to the next with no break. The boss portrait changes and the background fades from the current one to the next with each boss change. The blocks already placed stay there as well as any smaller enemies spawned.

This also shows the addition of retaliation to line clearing from the beetle and cobra bosses, as well as spawning those smaller enemies for the cobra and crocodile.

Hello World!