we kind of added that kind of message in this game that you can beat the game and reach the boss solo but it's harder just like in real life. Even this multiplayer game is hard to accomplish solo, which is why it's great if you can summon other players which lead to the theme "You need someone else". I'd be glad to play this game with you on multiplayer. Just hit me up when you're online and I am too.
Thanks for the feedback!