Sure! Here's a simple game where you can merge towers, upgrade them, and defeat enemies. The game will be implemented as a single HTML file and will use JavaScript. Please note that the game logic will be simplified for the sake of this example.
This game creates a game board with four initial towers. When you click on two adjacent towers with the same level, they will merge into a new tower with the next level. The merged tower will then attack the enemy. The game also includes a simple Enemy class and a test attack on an enemy instance.