The game is bloodlines of shadow springs.
What is the itch app I did not see one. Its odd because I can play the demo just not the full version
Viewing post in unable to play purchased game
See the Download app link in the sidebar on the homepage. And I see the creators are asking you to contact support, but support can't help with specific games. That said, you need to give more details. What happens when you try to run the game? On what operating system?