"I said at the very beginning that everyone looks at your graphic and that you have to deliver good graphics. But thats only the half, your gameplay needs also to be good!"

In my opinion it is the direct opposite at least at an Indie level
Put it this way
Commercial software houses normally enmployes 2 / 3 artist oriented people and 1 / 3 programming oriented guys
The reason is that graphics ia more time consuming than programming but it would be a mistake to assume that it is also the most important stuff

Lets take a 12 people team with 9 artist and 3 programmers
Useless to say that the reality is more diversified but it is just a rough example
You are a lonly wolf , good artist and good peogrammer and you want to compete with this team+
What would you do ?
Maybe you dedicate 2 / 3 of your time to graphics and 1 / 3 to programming ?
A bloody mistake

You are 1 vs 9 on artistic side , you will never win
Better to fight on the game play side
Here you are 1 vs 3 a little better

This is what the succesfull Indie designers do

Indie games graphics is normally rather poor but their game play sometime is great

In other words it is a strategy based on a simple benefit / cost analysis