Is there an issue with buying it here on Itch.io? The installer only included a 151KB JPG, two 3KB .IFL files, three 1KB .DAT files, a 1KB spreadsheet named License that is completely blank, and a folder named ".itch" which includes a 1KB "receipt.json" file.
*Edit to add - It seems it may be an issue with the new Itch.io app that just came out. When I clicked the Download link from the purchase confirmation, it started downloading the full game in my regular browser. So that's fun.