Poisoned Heart in Swampland (PHIS) Windows game

I did participate in this years Global Game Jam together with two other guys.

This years theme was the sound of a beating heart.

As you can tell from the name, the game plays in a moor. In the middle of the screen is a poisoned heart, which the player needs to cure by getting to it. On his path trough the hexagonal fields, monsters produced by the heart try to stop him. There exist 3 different monsters, with a different look and number of actions. To prevent that the monsters attack you, you can dig holes and guide the creatures into them. Digging and moving will make you lose one action-point each.

Controls

Left mouse button Move your game character
Right mouse button Dig a hole
F1 Change language (English / German)
F2 Change difficulty
F5 New game
Enter Skip round
ESCAPE Quit game

The game currently is free to play, but we may offer an improved version for few money later.

What do you think should be changed besides balancing the difficulties?
What would you like to have included?