Nope, you don’t need to be a Patreon to access it. It’s in the lab. Once you finish the intro there should be a sign that says “Debug Room” just above it.
I seem to be having the same problem. I have beaten each of the six options, but the guy at the Hall keeps saying that I haven’t won the first set yet. About the only possibility for my experience I can see is that I didn’t beat Mindy herself as she was already sized up before I could. I did beat the alternate that he set up when I selected Mindy though. Alternatively, with some of the other characters sizing up before I finished the first rank, it might require me to beat the alternates. Will test this when I can, and come back when I do so and post my findings.
I found a bug: when I encountered a Goblin during the mission to scout an npc’s brother in the mountain caves the game sends me back to the part where I don’t have control of my character to accompany the npc’s brother, so when I arrive again on goblin the same thing happens, causing me to get stuck in a loop (I’m using the same save as the previous version, so I don’t know if this could be something related to the bug).
One question: does the giant model to change the weight in the debugroom match the size we can currently get? If yes, what weight would be needed to reach it?
Do you have a save that’s just before the event? If so, send it to me and I’ll have a look what’s going on. I did test that event and it should work with no issues.