This was cool! It took me a while to figure out that jumping is what made a falling rock fall (sometimes? I think?) but impressive otherwise. I played until I got stuck (see screenshot) 
Viewing post in Spelunk't jam comments
Thanks for playing! Yeah the rocks fall each time you jump (unless it's a tiny jump) and only spawn if there isn't already a rock coming from that specific spawner.
Ah yes. You can restart each level by hitting 'R' which I tried to teach earlier in the game but I definitely could have done it better!
Thanks for the feedback