Osy Osmosis

Osy Osmosis is a game about helping Osy stay safe as she moves through her world collecting stars. You add or remove solute, called bits, to control water flowing into and out of her: too much water makes her swell and pop, while too little makes her shrivel.

Osmosis in play

Osy’s cell membrane lets free water molecules pass through, but water molecules bound to solute cannot. Adding bits to Osy binds some of her free water, lowering its concentration inside her and causing free water to diffuse in. Removing bits releases water molecules, raising the concentration of free water inside her and causing water to diffuse out. The game presents both bound and free water molecules as key parts of osmosis.

Levels and obstacles

The game has 17 levels that introduce new elements and obstacles:

• Bit vents: add solute to the environment around Osy, so you can add bits to match the concentration.
• Oxygen vents: give Osy a speed boost.
• Round crystals: are hard to move, though Osy could move them if she were bigger.
• Sharp crystals: can pop Osy, so you need to be careful around them.
• Pure water: contains no solute and has a higher concentration of free water, which continuously diffuses into Osy. Staying there too long can make her swell up.