When I’m trying to export for web / itch.io my tiles are all messed up in Firefox on Linux (it works in Chromium (but ewwww) and on FF mobile, weirdly). Here’s what it should look like (screenshot from Godot):
Any idea why that might be? It’s so weird, it’s happening only in FF, I suspect some anti-tracking addon but in Safe Mode WebGL2 doesn’t work, unfortunately (which is why it’s not running in Libre Wolf). The problem also happens in a private tab with all addons disabled (as far as I can tell). Mh, it’s working in Waterfox … What is this.
Librewolf has many, many basic web features either disabled or completely butchered to help with privacy.
If by Firefox you meant Librewolf, then there’s not a lot you can do to make the game run well.
However, I have tested your game on 3 different devices using a stock firefox install, and it seemed to work just fine for me. Maybe you have something misconfigured in your firefox, or an extension is messing with the game?
Oh, interesting that it works for you in FF (I meant Firefox not Librewolf), that’s reassuring that the problem is on my end, I seem to have messed something up in my FF install then, indeed.