When you kill a Wonder Stone in Fossilized Wonders, it may give you a life or a bomb piece. However, the amount of resources given differ between the trial and the full version.
trial: nothing > nothing > bomb piece > life piece
full: bomb piece > bomb piece > life piece
The trial version was scarcer in resources, the first two Wonder Stones wouldn't give you a life or bomb piece and the cycle was reset every 4 stones. In the full version all Wonder Stones give you something and the cycle resets every 3 stones.
There are other differences regarding the Wonder Stones between the versions, but they will be showcased in different posts. Please make sure to check the #trial20 tag for them.
EDIT (27-Sep-2025): Removed the detail about the health of the Wonder Stone since it might be a false impression due to the shottype difference (for example, some shottypes got stronger in the full version - one example is /post/795693731393175552/, which could mean the stones did not get weaker, instead the player got stronger). This needs more research.