That's fair, we don't support the functions tied to custom DLL loading xD

To be more precise, we support the entire "modern" function library in excel, that can be implemented without dependencies on Microsoft products/services. So if it can run locally, and isn't platform dependent, we run it. We, for example, support https://support.microsoft.com/en-us/excel/functions/filterxm... , so in some ways, we support more of excel than excel on non-windows platforms :P

We also support what-if scenarios, arrays, spills, cycles, all the non-cloud / non-DLL excel functions, data tables, conditional formatting, charts (though we don't allow creating / editing at the moment, that's coming very soon, there's a lot of configuration surface in those things, and we want the experience to be really good), etc. If you haven't tried it, maybe take it for a spin, I think you'll be pleasantly surprised with how much functionality we have.

Our biggest deficiency right now (in my opinion) is pivot tables, we don't let you create / edit / recalc them (though you can still build formulas on them). Our engine supports them, but we're still doing a bunch of testing on it to make sure it's rock solid before we turn them on for people.