Thanks for checking it out!
This is definitely something that needs to be playtested. I'm especially worried about the amount of attack dice I will have to roll even with the horde mechanics. I'll be updating it afterwards and probably expanding it a bit. Its nice to hear the lizards seem like a good enough telegraph for you, but another reviewer thought it wasn't enough. I guess the playtest will reveal that.
I actually struggled a bit with the page limitation so treasure and some concepts are probably not explained with full clarity. But my original vision for this adventure was to use the warband rules from Western Reaches and then have the army be the real treasure of the dungeon. But for a jam that would require me to reference rules in a non-core book so I decided against it.
I always try to keep an eye out for stuff to do for each core class and here the secret door being mechanical instead of magical is to reward the party for including a thief. Though at such a high level a wizard can just use knock, but at least I'm rewarding picking that spell.