Slowdown when you come up against the bosses

There is a huge slowdown when you come up against the bosses, it lasts 5-10 seconds and far too often it messes up my timing and end up in a lava pit.
6S+ 128GB
The game is great otherwise, easily worth 4*
The princess could use a facelift.

J Man F4i about Dragon Hills, v1.2.0