One tip I’ve found. You need to buy time. You can’t stop the clock but there’s one way around this. Instead of clicking the eye on top right hand side, which leaves you just with the background and all tiles removed, click on the Menu (next to the eye) top right hand side. The screen will go dark but you’ll still be able to see the tiles and furthermore, you can click and drag the brown panel in the middle and position it where you want. Whilst you do this, the clock stops thus giving you however long you need to study future move. It has help me for level 78,79.80 and 81.

I found helpful for level 78 to not use the hammer for it’s a pointless endever. But build up your power until you have not just the bomb but the mega fireball thingy and then put your mouse in the middle of the bottom thing and blow it to kingdom come. Now it will take 3 times to get ride of them as the first time will crack them the second will free them up and the third will get ride of them all together giving you the pieces you need.