The core concept of the combat system of TGB is to mix PuzzleRPG and Turn Based Tactics.
Thus, you can see that enemies in the TGB will move, attack and cast skills according to their own behavior pattern as the enemies in the Tactics Game. Meanwhile, player may change enemies’ position by matching the tiles or using skills.

Attacking
You can deal a normal damage to an enemy by collecting the tiles adjacent to it. Extra damage will be dealt if four or more tiles are collected at the same time. Prepare tiles ready to be matched at the position where enemy advancing toward by anticipating its action. Try to gather enemies together and attack multiple enemies with one single collecting. Evaluate the combat situation strategically while mastering the 3 matching skill and you will fight more efficiently.

Defending
This is a turn based game so after matching tiles the game will switch to the enemy turn. Like any other game, in the TGB, when your HP drops to zero, game over. Therefore, when you are sieged by the enemies, ceaselessly attacking is not a good option. Defending button will help you to neutralize the damage with your AM and wait for your opportunity to strike back. Of course, taking defend is not invulnerable. Using defend will end your current turn. You also must collect stone tiles to keep you AM above a certain level to cover the damage.

Collecting
You can deal damage by collecting tiles on the board and different tiles will bring you unique buffs. For example, collecting meat tiles recover your HP, stone tiles to recover AM, Mana portion to recover MP and so on.

P.S. If you have any question or suggestion about this game, feel free to let me know. 

Cheers, Wombo Combo Games