There’s a secret flag! I found it.

Where was it, Secret!

Just kidding, it was on the main menu, where? Open the inspector…

First, inspect the suspiciously Flag named object, then the UI.Text element, finally, there’s an element inside of it called text which contains:

GHCTF{I_guess_it_was_not_that_hidden}

Yep. That was it (I spent about 2 hours on this

BTW the intended solution was to run strings against the program files and grep for GHCTF.