The windmill is the wild symbol and it can substitute for all the other symbols, except the scatter symbol, to help and form winning combinations.
The Don Quixote novel is the scatter symbol and as well as offering scatter payouts of up to 100x, it is the key to the bonus feature.
If you land three or more of the Don Quixote scatter symbols anywhere on the reels you trigger the La Mancha Free Spins. You receive ten free spins during which a windmill wild will be frozen in the centre of the third reel. Furthermore, there is an increasing payout multiplier that starts at 2x and increases by 1x every two spins.
The Riches of Don Quixote offers a top payout of 3000x for landing five of the wild symbols along a payline. Don Quixote can payout up to 1000x, Sancho Panza can payout up to 600x, the girl can payout up to 400x the helmet can payout up to 200x and the shield can payout up to 150x.