Le problème vient de sytème utilisé pour le multi (p2p), en effet si UN joueur a une mauvaise connexion alors tous les autres joueurs vont avoir le même problème
Voilà le texte en anglais c'est mieux expliqué:
'The original game used P2P network architecture, which was ok for LAN, but not good for Online. We tried our best to improve the network code, but the game is still really sensitive to connection quality (not connection speed). This means if one of the players has a bad connection then everyone in the game will experience lag. There are some recommendations that can improve your overall multiplayer experience.
To get a better experience it is recommended to play with players from your geographic region (same country or same city). Also it is strongly recommended to close all applications that use internet connections (instant messages, internet browsers, torrent clients) for optimal gameplay. If possible avoid wifi-spots/shared connection, instead connect your PC with a ethernet cable directly to a router.