I'm sorry you got that error! The browser version is working fine, so this error most likely has to do with either your computer or your internet connection. Browser versions tend to have errors if the connection isn't stable enough, and if it's not that, then it's most likely your pc. I'm afraid I haven't heard of that metamask error before, so I wouldn't know a solution, but I'm certain that it's not related to the game itself, since I've checked it and everything's working fine (this is also the first time someone has gotten that error with one of my games)