I too cannot install this game using the itch app. There is no install file (as @benzoht mentions). Iirc, I think there is an option or something that the developer needs to check when uploading? Anyway, would be great to have this install through the launcher if possible.
Hmm iirc I wonder if you just need to select "executable" and ticked the Windows box on the game's dashboard? I seem to recall having a similar issue elsewhere and something as simple as this being the fix idk.
Actually, looking at your profile page, the games listed with the windows symbol showing will install but the ones without (including this one) will not. This might be it!