Well, if you were able to upload it, then it's not from itch.io's server limits. More likely the game itself. And I don't know what kind of mobile devices you're used to, but my phone won't load a lot of webpages. Even some that aren't any problem on the desktop.
Mobile devices are a lot weaker than PCs. Hardware specs are deceiving. And those 230MB of code and assets likely turn into 5 times as much in RAM, as a rule of thumb. That the game has to share with the browser itself, and the operating system.