Rian
Again, you have a great crew who really put out wonderful expressions and they work well together. This picture is even better than the skating one as the guys stopped movement by the same instant reaction and wonderment puts this image into a different league! (Still, your guy balancing his drink in the previous short was super cool, I must admit!)
As mentioned, the light on the faces can come down a tad. At the same time consider lighting the green basket and tires differentially to continue the sense of light from some spacecraft above to the right.
To be push things even further, one could have two overlapping shadows. One from the moon, very light and a harder one from the spaceship as it's nearer. This would mean shadows of the bikes and riders. Whatever you do, when you are satisfied, go away, then come back and reduce those shadows by 50%.
Not that you need any such additions. The picture works, is fun and zaps the sense with a big "TWANG!".
Asher