Okay, I'm really not familiar with the itch.io app, I'll download it and see if I notice something. Same goes with your save, I don't know how to extract it from the launcher. BRB as soon as I can.
You didn't notice anything on other games using webm ? It's only on seven sins ?
Hi, sorry for the delay. I've tried the game through the app and found the same issue than you. Honestly, I don't know why this problem occurs, I've contacted itch to get infos. The only thing I can advise you is to go to the parameters, open the game files and play with the html "index" which works fine.