In the latest update, I made it so that you can get diamond medals for each medal. Earlier, some medals had a highest level of gold, and others diamond for doing extremely well on the challenge. Now that they are all diamond, you can know when you have finished each challenge.
I also made it so the rocks are "solid". Now if you hit a small rock, it will bounce you a bit, and a large rock will stop you, instead of going through it. You can still pick up the large "loose" rocks like you could before. I have tested the races and increased the times to beat where rocks are a factor, so they are still achievable.
The Overachiever's contest is still on through the month of August! Only one person (other than me) has gotten the Blur 42 achievement, and no one else has gotten the Valedictorian achievement yet. Can you get either of these challenging achievements this month? If you do this, you have earned the honor to be listed in the credits for future players to see!