Thanks for playing!
There was restart button using the R key and one on the top right corner of the screen. Maybe It wasn't obvious, sorry.
Edit: Thanks for telling me about this. I forgot to add the reset button key controls in the description
Ha! Nice, now I see the button in the upper-right; somehow I missed that before. And it serves me right for not just trying the "R" key. But yeah, I'm glad you added it to the description. I was like "why would they add back and next buttons but not restart? that doesn't make sense," haha.