That's the point, he's charging $15 to support the development of a game made in paint, there is no need to support the development, he's just taking your money under the guise of 'support' the most he'd need is like $5.
Ok bro then try remaking this game in 10 minutes with AI and ALL of the features in the full version. This dev spent a year making this game mostly by himself and you're trashing on it.