If someone bought your game and couldn't run it due to issues on their machine (like not meeting the minimum device requirements), they might be eligible for a refund. Itch.io generally has a refund policy that accommodates customers who are unable to run a game due to technical issues. However, specific refund policies can vary, so it's essential to clearly state your game's system requirements and any refund policies on your game page.
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There is no drm on Itch. "Refunds" are a delicate topic therefore. Especially for works in progress. Even if your project does not run on the buyer's rig, it might run with the next version or the actual release version.
And if you do have a release version, you should know the specs pretty well.
I would upload a demo version to specifically give people an opportunity to test if they can run the game. And would consequently decline any refund claim for not being able to run the game. Should bugs be found, those can be fixed.