Credits are the in-game currency.
To challenge an opponent from the list or to play immediately against a random opponent you need one Credit each. This will only be deducted if the game between you is finished.
Credits are not absolutely necessary to play online: You don't need Credits to create games or to be challenged. If "Play" fails to find anyone who accepts your challenge after about a minute, you will automatically be connected to another free player without spending any credits.
You get 20 Credits as starting capital and can top up your Credits at any time with an in-app purchase (shopping cart icon at the bottom right) or by watching a short video. You can also invite friends for Credits. Just click on the shopping cart symbol and choose "Invite". You can now enter your friends' email addresses, and they receive an invitation with a coupon code for Credits. If one of your friends logs on to Schnopsn and enters the coupon code, you both get Credits.
We use the revenue from people buying Credits to cover our ongoing costs of running Schnopsn Online and to fund development of the app.