Hello, sorry that you encountered this problem. You should normally see a quick summary of the game controls on the bottom left side of the game when you're in the lobby. "Left" and "right" to move around, "space" to jump, "R" to reset a level, "Esc" to leave a level and "up" when you're in front of a door to enter the level.
If I may ask, what device are you playing on ? It could explain why the interface doesn't show ? Though I'm honestly not sure ^^ Let's hope we can figure it out so you can try the game as intended.
