Hot Gold Take It or Build It

Persistent Symbol is the most powerful and valuable top-tier special symbol found in 'Hold and Respin' bonus rounds. The core of this feature, unlike a regular special symbol (e.g., a Collector) that activates only 'once' upon appearing, is that it repeatedly performs its special ability on every single respin until the bonus round ends. This 'persistence' is what pushes the game's potential to its absolute limit.

Symbol Upgrade is a powerful feature that progressively converts low-value symbols on the reels into higher-value ones as the game proceeds. The core of this feature is not just a one-time symbol change, but a 'growth' structure where lower-tier symbols are permanently removed from the reels and replaced by higher-tier ones. This drastically increases the average expected payout of the reels towards the end of the round.