It's the start. The biggest turn-off is the start. I don't condone skipping to act 5, but I fundamentally sympathize with the people who did that because to incoming readers the game doesn't get interesting until it resolves the tension between "quest on a forum" and "actual narrative." The early acts absolutely have plenty of reread value, but to first-time readers the Problem Sleuthiness is going to be a turn-off and if they don't stick around at least until Davesprite's introduction then we've fundamentally lost them.

This is honestly a big part of why I'm invested in the idea of the adaptation happening. If it's good, great; if it's bad, at least I have a cheat code I can use to get people invested, I can tell people "watch up to episode X and then open the game and start reading from page Y."