Here are some of the obvious icons related to the theme, including the golden harp, the four-leaf clover, the Celtic brooch, the golden horseshoe and the silver ring; the lower values are the standard 9, 10, J, Q, K and A, but Decorated in shiny green.
It's hard to know how to make another Irish-themed slot, but it's very fun, it's high quality, and the free spin offers some extra stuff. There is no reason not to try it, the RTP is 94.25%.