I already played the demo and i really want to buy and play the buy version. But i am afraid to buy again and again just to update the game. 

Updates are free, what kind of game does that? Please tell me I am super curious.

you only need to buy the game 1 time, updates are all free if you own/buyed the game once, like any other game.

for more details about the game i would recommend joining the dicord server with the roomlink.zip