Well, that doesn't really cover what's been happening here. First of all, this isn't developing some new piece of software from scratch. It's effectively a glamorized comic book made in RenPy with a couple of somewhat trivial extras added. The bugs that they constantly spent time fixing aren't something that would be accepted as regular bugs, or at least their fixes aren't meaningful bug fixes.
What this amateur has been spending time fixing would be the equivalent of having a document where the software can't handle line breaks. He changes one word early in the document, and then he has to manually go through all the text and fix the now incorrect line breaks. The bugfix would be to fix the line breaker or perhaps remove the functionality alltogether. Instead he's patching details that are caused by bad design- and architecture choices.
As for having a QA department, for a RenPy game as simple a this, I'd say that would be overkill. You just need to be a bit structured, identify where the game can branch and thus have things happen in 'wrong' order and then walking all those paths, checking that nothing breaks. It is as trivial as software testing can possibly get.
To complete this, the bug many people encountered during Gomira's flashback convo was due just to an accidental keystroke while fixing some typos. Testers never found it because it wasn't there before the final build was distributed, and this final build was never properly tested because, in theory, the only changes made were some typos. It took him less than 30 minutes to fix it and upload a new build; sadly many people here had already pirated the original build and now seem unable to install the hotfix.
The other major bug found after the release were only present on Mac and Linux builds due to a wrong filename. This took a bit more time to fix because, at first, it couldn't be replicated on a Win environment, until someone suggested where to look at. It's now fixed too.
So what this amateur has been spending time fixing before the release, indeed, were not traditional coding bugs, but mostly story and dialogue inconsistencies created after they felt they needed to include major changes to the first 'alpha' build, completed back in April. Many scenes had to be entirely redone, others had to be heavily edited to shorten them or make them less dull and more exciting, and some completely new scenes had to be created too. Whilst creating the new art and convos needed was labeled under 'edit' tasks, everything had to be re-posed and checked again to see if these changes actually worked as they intended. This work was labeled under 'debug' tasks even if it only implied going through the game over and over again, or looking closely at the character's poses to see if they matched the new dialog lines. To let patrons know they were actually working on the game during any given day, they just added a task to the debug count even if they hadn't actually fixed any 'bug'.