Slot game suggestion-
• when hitting a free spin combo, when the reel starts for the free spins- if you hit certain reels that win crypto, make the reel with the specific win pause while the free spins continue. As you continue to use the free spins and hit any more of the winning theme/picture, allow them to pause and continue until all spins are completed. The amount of winning themes that hit provide a multiplier at the end of the spins to multiple your winnings.
• second idea if you hit a certain number of specific themes allow 3 boxes to appear that the player can decide to pick, which will provide a multiplier or a number of free spins.