I bought the game with the Bundle for Ukraine. I unpacked the file "card-hog-windows.zip" somewhere on my hard disc. When starting "CardHog.exe" on Windows the following error message appears. When clicking OK the same error message appears again. And again. And again. Only way out of the loop is to end the "CardHog.exe" process using the task manager.
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Card Hog: CardHog.exe - System Error
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The program can't start because steam_api.dll is missing from your computer. Try reinstalling the program to fix this problem.
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OK
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Workaround: I copied the file "steam_api.dll" from another game (Terraria in my case) in the same folder with the file "CardHog.exe". Then I manually started "CardHog.exe" which opens the game window.