Thanks for raising this, I'll take a look when I get the chance. Firefox mobile can be quite tricky, and I must admit that I completely forgot to test on it before taking the site live - my apologies!
You may think this seems quite familiar to another post on here! I'll explain:
We've been working on this idea for about 8 months since first prototype. We basically had everything finished and ready to launch, but unfortunately for us, Neal Agarwal (of neal.fun) had almost the exact same idea!
We officially launched a couple weeks ago at this point but at the time my submission here was getting caught by the spam filter - trying again now that I have amassed some karma.
Would love if you could give our version of the concept a chance! We think it's much more fleshed out - for starters, your items actually get saved between sessions.
P.S. Sorry about the slightly obnoxious new discovery animation - there's no way to turn this off yet but we will add a way of disabling it soon - we agree that it's rather annoying in the early game where you are constantly discovering new items!
Will add an ability to speed up/outright disable animations in the next update! Was a bit of an oversight on our part as once you start amassing a decent amount of items you encounter the new item animation less frequently - but in the early game it's definitely quite irritating!
Completely independently! We're a team of two University students funding this out of our own pockets. About 8 months work (on and off) from first prototype.
Was working on the very same idea alongside a friend of mine, we happened to launch a few weeks ago. Quite a lot more fleshed out than Neal's version, if anyone wants to check it out!