It look like the creature numbers in the NPC-generated invasions don't follow the modern creature numbering scheme where the first one to arrive remains number one, and so on. With the incredibly enormous number of creatures that these things spew out, there's constantly dozens of creatures moving in and out of each room and it's pretty much impossible to target a specific creature since its identification number is constantly changing. This is compounded with the rock guardians in particular, since they all use the same noun. Is there any chance this could be updated to behave like normal creature numbering does these days?
On the subject of the number of creatures that are there in the first place, it seems like it would be better if it could be somehow related to the number of people participating. There doesn't need to be 26 creatures in each of 12 rooms when there's two people participating. It just makes for unplayable levels of screen scroll as they constantly move from room to room because there's nobody for them to engage. Creatures continue to spawn throughout the invasion anyway, so there's no need to flood them out like that.
Thanks,
-Life Weaver Karthor