Grindstone is a colour-matching puzzle game, where you plot the right path through each grid level to attack enemies and gain treasure. The aim is to join together as many similar coloured monsters as possible in one go.

You plot a course from square to square, moving vertically, horizontally and diagonally to chain together the most matching items and trigger combos. If you finish your turn next to a monster they hit you and take life points away. You finish the level once you get to the exit at the top of the screen.

This means that you can take as long as you like at each level. But the longer you stay the more monsters appear. More chance for hacking and slashing them for points, but also more likelihood of being overwhelmed. You need to take extra care as your health doesn't restore between levels. Along the way, you can pick up useful items and gadgets.

It's a well-balanced puzzle game that tempts you to go for more loot, but also punishes you if your greed outstrips your puzzle-solving abilities.