The forbidden word: DLC
Dashes & Squares will have DLC, but you won't obtain advantage by buying them, the main focus of doing this is long term support, they will contain skins, song and, some times, map pieces.
There will be 5 DLC at launch, one of them being free.
Two of the DLC at this moment has Steam page!
https://store.steampowered.com/app/2592250
https://store.steampowered.com/app/2655530