Big Bang Boom

Bet levels from 0.25 to 100 buy into Big Bang Boom, a highly volatile NetEnt machine that pays out at up to 96.07% RTP across five configurations, tops out at 4,300x the stake, and starts every spin on a 4x4 grid framed by three rows of hidden positions above and below it. The studio built the whole thing around Bomb symbols in place of a wild, so nothing substitutes here — the bombs carry the game instead.

As wins or bomb blasts uncover more of those hidden rows, the grid stretches taller (never wider), and the number of ways to win rises from 256 at the smallest size to 10,000 once it's fully open. J through A card faces cover the low end of the paytable at 0.16x to 0.2x for four matching symbols, and a smiley face, a butterfly, a heart and a crown sit as the four premiums, worth 0.4x to 1x for the same four-of-a-kind hit.

Any winning combination or bomb explosion clears the affected symbols and lets the grid avalanche new ones down to refill the space, looping until a spin produces neither a new win nor a live bomb. The bomb set covers straight-line blasts along a single row or column, diagonal hits at the corners, a cross-shaped burst in all four directions at once, one that clears everything touching it, and two more specialised types — one that pops random covered positions, and a free-spins-only bomb that keeps detonating on every spin once active until the round ends. A pair of the bomb types can also turn up through the Treasure Prize mechanic, which surfaces whenever expansion uncovers a fresh position on the grid.

Reaching a full 10-row height on every reel in the base game hands out 6 free spins on an expanded 4x10 board, capable of growing to 8x10 with two more reels on either side. Prize symbols worth x1 lock into place once they land during this round, and each time a bomb detonates over one its value doubles, climbing as high as 2,048x before every locked Prize is added together and paid at the round's close. The Treasure Prize mechanic can also hand out a direct 16x, 32x or 64x pay, or an additional spin, while it's active in free spins.

Buying in costs 75x the stake for the six free spins outright, or double that for the same round with one of the persistent, always-exploding bombs already placed on the reels from the very first spin.