Press the green flag to start. Then wait a couple seconds for the mirrors to be placed. Click on the mirrors to rotate them. Try to get the laser through the gap in side of the board opposite from the start. If you shoot the laser into a wormhole, it will come out of the other one that's the same color.
All credit to @JereTheJuggler for the project. I just made it work in Scratch 3 Press "L" to select level.