And finally, and of course something that I wouldn't have discovered without reading about it (since it requires doing things that anyone on their sane mind would avoid), there's a full-on Monkey Island Easter egg hidden on the final level of Indiana Jones and the Infernal Machine (Level 16).

In order to find it (spoiler alert), once you arrive to a room with a well in the middle, you must fall through the well, then go back again to the cubic structure the level begins with, travel again through the orange tunnel (that leads to the Palawan island piece of reality) and now there will be a tunnel opposite the portal to Palawan. If you go through it, Indy enters a room inspired by the barber shop in Puerto Pollo from Curse of Monkey Island, Indy physically changes into Guyrbush's model (from the cheat code I posted about before) and the music changes accordingly. I attached some pictures.

I can't begin to fathom how anyone would discover this on their own without looking at a guide... It's cool to see but the Aetherium was my least favorite level to navigate. I actually missed it the first time I completed the level and I had to replay to get to see it.