Neptune's Riches: Ocean of Wilds
As the title indicates, you can look forward to a lot of wild symbol action in this game. The 3 middle reels are framed, and you will see a lock sitting on top of each of these reels. You need to land at least 1 key on reels 2, 3 and 4 at the same time to unlock all of the locks. This triggers the Rising Wilds Respins feature.