It looks funny. At first I could not understand why I can not press C on level 1. It turned out I had no portals and they are playful. (I did not read the description, if I understood by typing, it means the game is intuitive)
The only thing is that it’s difficult, and it would be worth re-running when the portals change, a message pops out that the portals are over. I didn’t think about looking in the left corner