Fully unlocking the reels in base game activates the free spins. In free spins, the reels reach up to 9 symbols tall.
The progress of unlocking the reels in free spins does not fully reset between each spin. It is only reset down to the shortest reel. There are 3 free spins modes:
Before playing free spins you will be able to increase the amount of free spins by spinning the gamble wheel. Losing the gamble takes you back to the base game without playing the free spins. Starting free spins are 5. You can gamble to increase it to 8 free spins. Win the next gamble to increase it to 12 free spins.
The gamble wheel can land on a special golden field that gives an opportunity to win up to 12 free spins on the first gamble and up to 16 free spins on the second gamble.
Gamble 1:
Gamble 2: