Right click, go to proprieties, permissions and check "allow to run as a program". It should work

He said in one video that the finished game will cost 5-10$.

Amazing! The only thing i would add is a restart button, it's a little bit annoying having to close and open the application for every cat fact.

The rest is perfect!

You cannot even play the game. There is just a .ink file that does nothing. It's not even a game. It's just a compressed piece of shit. 0/10

Thanks!

If you mean the Cubethon made by Brackeys, then yes, i used his tutorial to make this game. 

If you mean something else please clarify.