This is a typo error we have missed. Unfortunately we cannot change the text of the pledge after the Kickstarter page goes live. You will get a free digital copy of the game. No need to pay more afterwards.
We are using the Unity3D game engine which was recently made compatible with Linux. We did not imagine that the number of people interested in a Linux version of the game would be this large, so we did not implement it yet. If everything goes as intended, we will be able to announce the Linux version of the game a bit later, in one of the Kickstarter page updates.
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