Hey Fiekie
This is how it works - in free games you can choose your symbol. Each symbol symbol/group has a different volatility. Want to "feel it", play the game in demo mode - choose Buffalo/Eagle - these are the highest volatility symbols. Means when you hit them with expanded reels, you really hit big.
Then try a few rounds with lower ranking symbols, 10-Ace. You will see/feel the difference.
Get the Buffalo, 3 symbols expanding, just 3 pays 100x your bet. It will be hard to find another game that does that 3 symbols paying 100x
Just to be sure, did you know that if you click on the arrows to left/right of book you can choose different symbols?