The titular Hot 1 feature is what all players are aiming for when they play this slot. In order to get to that feature, though, you will need to work your way through the Free Spins round. This is triggered when players manage to land three or more Bonus symbols. When this happens, you will initially be rewarded with seven free spins.
During these Free Spins, the Bonus symbols will become Sticky. There is also a Premium Symbol Trail across the top of the reels in order from lowest to highest paying. On the first Free Spin, all of the bonus symbols will turn into the lowest paying symbol, and this will ascend with each Free Spin. If you land any more Bonus symbols on a Free Spin Round, you will get an automatic respin, and it will be held in place.
This all leads to the Hot 1 spin, where the highest symbol in the game, where all Sticky symbols become the Medusa Wild. This, in combination with the potential retriggers, can lead to some huge payouts, with all Wild symbols providing a 2x Multiplier for wins as well.
There is also a Respin feature which is rewarded if you just manage to land two of the Bonus symbols. When this happens, the two symbols will hold in place, and you will get one respin. This respin can vary though, with there being three options. The bonus chance option does not make any changes, the Medusa Wild respin changes the two bonus symbols to Wilds, while the Medusa Power respin is the most lucrative, turning the two bonus symbols into 5x Multipliers.
If you want to get into the bonus rounds when you start the game, then you can use the Bonus Buy feature to get in for a 100x your stake option.