Thanks for playing! In an update we'll look at making the health stay the same between rooms. We initially wanted each level to be its own challenge, but we agree it'll probably flow better having each level go into the next or perhaps have chunks of levels where health must be maintained.
There's an issue on Chrome where if you drag your mouse and it thinks you're trying to move the canvas, it holds onto the current input. We'll find a fix or change the game to a Windows build for the update we have planned.
If you don't mind, what browser are you using? And were you playing in the browser window or in fullscreen?