The Jammin’ Jars slot game has a total of 5 bonus features. Winning clusters lead to Collapses/cascades with Jam Jar Wilds containing an increasing multiplier. The random Rainbow feature sees giant fruit symbols land on the grid for guaranteed wins. In the Free Games feature, Jam Jar Wild multipliers can only rise, with no limits.
Collapse
When a winning cluster of matching symbols lands, the Collapse feature is activated. Winning symbols disappear from the grid with existing symbols dropping down into the newly-vacated spaces. Then new symbols fall in from above. This allows you to form another winning cluster. This process is repeated as long as winning clusters are formed.
Rainbow

When no winning cluster is formed, the Rainbow feature can randomly trigger. A rainbow animates over the grid and adds 1 or more giant fruit symbols. If matching symbols appear adjacent to the giant fruit symbol, they will become part of the winning cluster for a bigger payout.
Jam Jar Multiplier

Keep an eye out for the Jam Jar Wild symbol being part of a winning cluster. If so, it moves to an adjacent and empty position before the next Collapse occurs. These Jam Jar Wilds are held in position too.
Importantly, Jam Jar Wilds have multipliers which increase by 1 every time they are of a winning cluster. The multiplier value can increase with no limits. When no wins occur, they drop off the reels.
Free Games

Landing 3 or more Jam Jar Wild symbols anything on the grid during a base game spin will see you trigger the Free Games feature. 6 free spins are then awarded. If you trigger the feature with any Jam Jar Wild multipliers, they will be carried over to the free spins.
If a Jam Jar Wild contributes to a cluster win, the symbol randomly moves to an adjacent, vacant position before the next Collapse. Held in position, the multiplier increases by 1. Unlike the base game, multiplier values can only rise meaning bigger wins potentially.
Bonus Buy
Not available to us mere mortals in the UK, there is an optional Bonus Buy feature that was added to Jammin’ Jars back in October 2021. It allows you to buy your way into the Free Games feature for a fee of 84 times your total bet. If playing with the highest RTP setting (96.83%), the RTP for this feature is 96.49%.