Rock Burst is a match game that goes downwards. You are looking at a window into a mine shaft, six across and nine deep, and the only thing that matters is the floor. Tap any patch of three or more touching rocks of one kind and they come out. Nothing falls into the space they leave. The hole stays a hole, exactly where you made it, and the wall around it holds.

That is what makes the digging feel like digging. To go deeper you have to empty the entire bottom row, all six rocks of it, and the moment you do the whole shaft drops a metre. Everything shifts down, a fresh seam appears at the top, and the depth counter moves. Holes you left higher up come down with you, which means a careless blast in the middle of the wall follows you for the rest of the shaft.

Every shaft asks for a number of metres inside a number of blasts, and later shafts ask for more of the first with less of the second. Larger patches pay far more, since the score grows with the square of the patch size, so there is a constant argument between taking the wide seam for points and taking the awkward corner rock that is blocking your floor.

Two tools come with each shaft. The drill takes out one single rock anywhere you point it and costs no blast, which is exactly what the last stubborn rock on the floor needs. The charge blows out an entire row of your choosing, once per shaft, and pointing it at the floor is the fastest metre you will ever dig. If the wall is ever left with no patch to blast at all, loose rock caves in from above so you are never stuck.

Eight finds are earned for wide seams, deep drops, tool free shafts and total metres. The digger board ranks your best shaft against the rest of the crew.

The game is portrait, works offline, and has no account, no advertising and nothing to buy. Everything is stored on your device and the settings screen has a single button that clears it.