Great game with a fatal UI flaw. The tooltip on "Reset" explains that time crystals are based solely on the amount of rocks you've collected. I didn't see this for the first two resets, and was ready to write the game off.
After seeing that, I realized I'd spend 3-4 minutes progressing, then the last 1-2 minutes completely focused on collecting rocks. I took a different upgrade path every reset depending on how much time I had available, and this kept the game interesting right up until I crashed it (after getting the last upgrade, so I still "won").
It's also possible to do quicker runs in the beginning and get 2-5 crystals, which is optimal, but maybe not as fun.
If you can find a good way to message this, I think people could have a lot of fun with this.