If all block symbols are destroyed in a cascade, then for the rest of the game round, only Multiplier, Bonus, and Gem blocks will appear in the blocks area.

Block Set Upgrade is a persistent reel modifier where, after all block symbols are cleared from the grid in a single cascading sequence, the available symbol pool for future block drops is permanently enhanced.<br>This powerful feature ensures that for the remainder of the current game round (typically a bonus round like free spins or super free spins), only high-value Multiplier, Bonus, and Gem blocks will appear in the designated blocks area.<br>It significantly shifts the game's volatility and payout potential by removing lower-value or generic block types.