Upgrade to complete edition ?

[Doctor Dementor]

So decided to come back playing the game but then saw that a complete edition is available to purchase but :
-If i buy the complete edition steam key outside steam does it count as an upgrade ? a separate game ? or it wont let me install it saying i already own the game ?
-does it require a fresh new save to play the content ?

[Sagiri In The Dark ⁴²]

I see all dlc characters in friend list. But I'm not buy this.
May be bug?

[Stijn Davids]

I just bought the complete edition, but in my case i didn't have already the game. Btw i did a similar thing with other games and they counted as upgrades so i guess it will work like this for fatal bullet too, and no, i don't think you need a new game to play them since as soon as you log-in it will show you a pop-up with all the upgrades so also if you continue your save file they should be immediately available

[Doctor Dementor]

ay thanks man