Yggdrasil has built on the original game by adding some really good bonus features. The Free Spins Round from the original slot is still here, but some changes have been made. In order to trigger the round, you will need to land five or more Scatter symbols. Each Scatter symbol you land will reward you with one free spin. Remember that the Gigablox symbols will break into separate symbols, so a 3x3 Gigablox will give you nine symbols.
When the Free Spins Round starts, you will be randomly rewarded between 3-7 bonus features. You can choose to gamble the number of free spins and bonuses you have at the start, though this can backfire, so approach with caution.
You will then be rewarded a combination of features. The wild fish transforms a fish symbol into a Wild, the 2x Multiplier does as it says on the tin, the extra Wild adds more Wilds to the reels, the fish stack adds Stacked symbols, and there is also an extra Free Spins feature. Perhaps the most useful you can secure is the Expanded Reels bonus, which expands the grid out to be 6x6, and ups the paylines from 25 to 40.
These bonus features and free spins complement each other nicely, and they also work really well in tandem with the Gigablox mechanic.