Machinarium: Tic Tac Toe
This puzzle really ruined my enjoyment of the game for a while. Partly the number of locations you have to traverse to get the various bits and pieces is too big but also there is no real logic to winning the game.
As the computer goes first, technically it should never lose. I had to read some advice on a forum about using a chequerboard pattern (basically trying to form a loose grid of x shapes) before I could get past it. Sure enough if you use the pattern and you play long enough and block any three in a row lines it forms the AI starts making some mistakes that allow to get five in a row.
It’s a shame because so much of this game is beautifully formed.