The biggest problems are these:
The manual says nothing about the limitations (drawing canvas not being saved, waits not being saved even though there's no networking done). So we're left to test and guess.
and
We need to strip down huge projects to repro a bug, fair, but we also pay for C3, so at this point we're doing QA, and we pay for it. which is not as fair as I'd expect.
I know small time game devs that hired QA companies to deal with their bugs, surely Scirra can figure out something. Plenty of good bug hunters on C3's github issues.
Do you know how much it took me take to strip down these to report some bugs? Days. And as yours, my time is also not free.
If C3 would have some paid testers, they could be the ones to strip down the project on our behalf, the clients, in order to find bugs in C3.
If C3 actually wants to fix bugs and not rely on the game developers to do half of the job.
I was a tester for EA Games, it's not easy work.