By purchasing PREMIUM you get:

• Kink Skin!
  
• Access to special weapon: SeaWeed!
  
• You buy me food and support the further development of the game ;p

In the future, a single-player campaign involving solving puzzles on non-standard boards is also planned. This campaign will be available only to PREMIUM users and after its release, the price of this DLC will increase (those who bought it earlier will of course not have to pay extra).

About SeaWeeds:

This weapon attachs itself to a coin and can serve a variety of functions, both defensive and offensive.
When used on one's own coin, it acts as a shield for it, i.e. when a coin flies into the SeaWeed, it explodes, but also repels the attacker (towards the closest enemy of the SeaWeeds's owner). When used on an opponent's coin, it allows you to take (co-)control of it in subsequent rounds as long as the SeaWeed is alive (and gorging). Additionally, each weapon modifies its effect to a greater or lesser extent when used on a coin with a SeaWeed on it - check it yourself! :)
When the SeaWeed touches the coin, it jumps forward, but at a random angle, which you can also use to try to capture your opponent's piece. Remember, however, that you cannot touch coins under "virgin protection" with your SeaWeed. There is also a "SeaWeed protection" which means that when a coin with a SeaWeed falls into the water, it is returned to the board.