Itll be free, and its out in August.
Vampire Survivors devs poncle confirmed that the upcoming multiplayer mode would be released as yet anotherfree update.
Poncle said that Vampire Survivors basic gameplay stays pretty much untouched despite the extra players, witha few tweaks.

Youll also all need to be different characters, so disagreements might occur before you even hit start.
So, no huddling up to share different ends of the same keyboard.

