The tap-then-roll loop is a neat hook: the mallet upgrade felt good right away, and rolling into the ladybug and snail with a smash combo is satisfying. What I noticed after two rolls is that the rock came back smaller each time (12g to 9.4g, then 9.6g to 7.4g) and the Snail blocked me both times, so it wasn't obvious what to do differently. A short hint after a failed roll, like how much weight the Snail needs or a suggested upgrade, would make the next step clearer.
Thanks so much for playing and for the detailed notes!
You're right, this part wasn't clear enough. Rolling wears your rock down a little each time (that's the cost of a roll), and the ore you bring back buys upgrades. The Snail needs about 23g, so keep tapping (or let Auto Growth work) until the "Next" bar under your rock fills up, then roll again.
The game did show that bar and a few suggested upgrades, but they were easy to miss, so I just pushed an update: when something blocks your roll, the results screen now shows exactly how much weight you need (for example "Weight needed 23g, now 9.2g") and suggests the growth upgrades. Thanks for the great suggestion!