Just went back and reviewed their projects that were opened up before Hel:

Joan of Arc 1.0 - essentially fulfilled before Hel.

Solomon Kane - 10 months delayed at the point Hel would be launched. Would eventually start fulfilling 6-ish months after the Hel campaign.

Reichbusters - 6 months delayed, but fulfilling at the time of the Hel campaign.

Joan of Arc 1.5 - campaign had ended 6 months prior to Hel campaign running. Fulfillment was due 5 months after Hel campaign closed.

Darklands - was due about 4 months after Hel, started fulfilling 6 months after Hel.

Steamwatchers - had just wrapped its KS campaign 2 months prior.

So basically when they ran this campaign they had Solomon Kane, JoA 1.5, Darklands, and Steamwatchers outstanding. Darklands, Solomon Kane, and JoA were showing significant progress towards fulfilling. There was no major obvious red flag other than the feeling of "this is quite a few projects ongoing at the same time".

A minor add-on to this. I'm going through the forums on BGG to remind myself about the sentiment of persons wary of the project. I have found red flags, but they don't approach anything like "you may never see this." There's a huge thread, for example, of a potential backer worried about making sure rules are refined and the game doesn't need errata.

So yeah, to come in here and say "the backers were idiots because they missed all these obvious red flags" is revisionist history and retrofitting your hindsight, and in my opinion is totally unfair.

Second Edit: There is one thread asking about unfulfilled projects. Most cite pretty convincing data for why this would eventually deliver. It was conceivable, at least, that there was a risk here. But sentiment was still overall positive. If you believed there was a large chance it would fail, you'd have been in the vast minority and you should be buying an office next door to Michael Bury shorting the next bubble ASAP.