The corner method

Most good Gumnut Merge games look the same from above: one big tile in a corner and a chain of smaller ones running away from it.

Choose a home and stay there

Pick one corner, say bottom-left, and keep your biggest tile in it for the whole game. A big tile in the middle of the board blocks merges in four directions; in a corner it blocks only two, and the rest of the board stays free to work.

Two directions, a third when needed, the fourth almost never

With a bottom-left home, down and left keep the big tile in place. Right is safe while the bottom row is full, because a full row cannot slide. Up is the move that drags the corner tile away, so save it for the moment when nothing else moves, and repair the corner straight after.

Build a chain, not a pile

Along the bottom edge, line up tiles in falling order: 256, 128, 64, 32. When the smallest end of the chain gets a partner, the merges run back along the row one after another, and a single move can ripple all the way into the corner. Feed the end of the chain, not the middle.

Undo with a purpose

Undo restores the board, the score and the random state, so the tile that appears after a move is always the same. Undoing to get a luckier tile does not work. Use undo when a move broke the chain or pulled the corner tile out; on Hard you only have three, so keep at least one for the late game.

When the board gets tight

Late in the game, look for the move that creates a merge rather than the one that only slides. A board with even one pair left is never lost. If you have to break the corner, do it with the move that leaves the biggest tile on the home edge, and fix it on the very next turn.