Are the free spins rounds in Thunderstruck 2 retriggerable?
No, the four main bonus rounds (Valkyrie, Loki, Odin, Thor) cannot be retriggered with more scatter symbols once they’re active. Each round is a standalone feature. That said, the rolling reels mechanic in the Valkyrie and Thor rounds can create chain reactions of wins from a single spin. This extends the action without needing extra scatter symbols.