Hi John, I test you game this is my feedback.
Positive
I like how game play is quite simple to understand. When I play, I see 3 unusual ways to make player game over as hit the red ball, touching the yellow floor, and stand in the black mist I like how to add black mist moving approach player every time pass it make as long as player survives, the harder the game becomes.
Negative
When I player collect the fossil, they do not get anything, that is why players see fossil they did not go to collect it. You can add a score system to your game like how long you survive you get more score or get some score after collecting the fossil. It gives players reason to survival or collect fossils. The last problem I see is platform, platform in this game some of them is too far and sometimes I did not see any platform to go next, I need to drop out of the planform to random it has any platform under it.
Overall
I think you can zoom out the main camera to make the player see more platform in the map or make the platform gap between platforms smaller. Finally, I am very enjoying your game and good luck with your submit.