Well, this is a game I started not too long ago. I decided not to finish developing it because it was a gameplay concept I didn't like very much. While it isn't finished, it is fully playable.
The Elements is a puzzle game where the player uses the four basic elements - earth, air, fire, and water - to remove other elements on the field. There are obstacles such as portals and boulders.
The main controls are:
1, 2, 3, 4 to switch between water, earth, fire, and air respectively
Space to fire
Left/Right to move
The controls are fully customizable under the options menu
Please read the instructions or you will probably become lost ;)
Last but not least.. don't mess with the level editor if you don't immediately understand how it works... its how I created the levels, but it is slightly confusing - enjoy!