probably doesnt exist so you can somewhat tell whats happening, 2x speed would just be stats going insane and health dropping

This was an actual feature in earlier versions of the demo, but it got taken away due to technical issues or something.

Since the results of the fights are essentially pre-determined from the start (you can't actually do anything mid-battle), I would agree with putting this feature back. Especially in the higher ascension levels where you and the enemy have a lot going on in terms of attacks, recovery, thorns, and so on, the details of what happened is probably best expressed in the stats at the end of the battle anyway.