The gap between theoretical and observed RTP is worth noting. It suggests that many operators deploy Starburst at sub-default RTP settings. Players who care about RTP should always check the in-game paytable rather than relying on the 96.09% figure quoted across review sites.
According to NetEnt's specifications, approximately 22.6% of spins (roughly 1 in 5) are expected to result in some kind of win over the long term. This figure comes from the game's official documentation, though it has not been independently verified by a published third-party audit.
A winning combination requires three or more matching symbols on consecutive reels along an active payline, starting from either the leftmost or the rightmost reel. The payout is determined by the symbol's value (see the paytable below) multiplied by the coin value and bet level.
Because paylines read in both directions, a sequence of five identical symbols across the entire grid counts as two wins, one from the left and one from the right. This is why the BAR symbol, for instance, pays 250x for five of a kind from one direction but effectively delivers 500x total when you account for the both-ways mechanic.