I do like the idea of going back or forth in time as a character only ability to gain advantages. However it doesn't feel dynamic switching between them. Just standing and witing for time to rewind feels off. If it would have been some sort of ability you have to trigger by pressing a button. Adding the health bar as a sort of punishment for the player for rewinding too often in a certain time period would have been possible then too. But anyways, i'm not here to judge you or your idea behind it. It has potential though.