My idea was to have one launcher from where I can sort of navigate to the other platforms without having to start them. This Homescreen will give me info on everything that is happening on every platform. 

You can navigate between the platforms you have selected and for example install the game you want without having to start anything else. 

Detailpages of a game will also give you the option to look for cheaper prices. Be it from other platforms or via Keysellers. Discord integration would help you to find other people interested in this game. 

Communication should not be a thing of different platforms. Let's have one seemless experience that is not constrained by the software you're using. 

Have a profile page where you or others can see ALL the progress you made. 

As mentioned in the beginning this was just a small experiment regarding this topic. I wanted to see what this actually looks like and what constraints would occur with this. Way too many as I found out. Imagine having to explain that you will show them the cheaper prices of their competitors ;)