Big Bad Towers Slot by Playtech

Three heroes lean over the castle battlements above the reels: a blue-caped archer, a crowned king in green, and a red-hooded wizard. Each one owns a coloured Flag symbol, and those flags are a second way into the bonus. Six or more Scatters open the Free Games the usual way, but a single Blue, Green or Red Flag landing in the base game can also fling you into the feature at random, dragging that colour's Character Perk along with it. Mystery symbols work separately. On a winning spin they land in a batch and all flip to the same random symbol before the payout is read, though they never reveal a Flag or a Wild.

The feature itself is a collection round built around a siege. You start with 6 free games on independent reels, and the Scatters from the triggering spin stick as Frames. Each new Scatter after that either drops a fresh Frame or upgrades one it already sits on, climbing through the levels, while a loose +1 Free Game symbol tops up the counter. When the spins run dry, every Frame becomes a Tower and pays a random prize scaled to its level. Level 1 Towers are pocket change, Level 2 tops out at 20x, Level 3 can reach 100x total bet.

The three Character Perks are what bend those rules. Blue adds a sixth row for extra Frame space. Green spreads up to 10 Frames across the grid before the first spin runs. Red is the one to chase, since it unlocks Level 4 Frames, and a maxed Level 4 Tower pays up to 1000x total bet from a single position. Perks stack in any combination, or none turn up at all. Hitting the Buy Bonus switches all three on together, the only route that guarantees those Level 4 towers are in play.

The art keeps things light. A bright, sunny courtyard sits behind the grid, ringed by a stone curtain wall, green-roofed timber houses and the three tournament flag poles off to the left. Purple cannons and wooden catapults fill the mid-tier symbols, bold card royals handle the low end, and a fat green cartoon dragon presides over the whole medieval scene. Playful stuff, closer to a mobile strategy game than a fantasy epic.