Inspiration: I see the DNA of Super Contra here, for sure. Shadowdark + firearms with frequent mishaps = CHAOS. Nice.
Usability: A little reorganization would help with usability. I'd suggest moving pages 2 and 3 after the two new class pages. And further differentiating these two new classes from each other would make them more appealing options. The way this adventure is set up, I think it would work especially well for solo play.
Vibes: I love the art. The bearded dwarves, orcs, and drauger with giant heads are awesome.