Secret Area clues/hints?

[seancornball]

I know about the area in the plaza (for those still looking: follow the footprints/scuff marks!) and also that there is obviously something behind the door in the Engine Room once you obtain proper captain rank. (Which I think I've accidentally spoiled for myself.)

Are there any other areas, though? If so, without spoilers, can I have hints? I.e which floor and maybe what to look out for? Mostly I just want it confirmed whether I should be looking for additional areas or not. I feel like I've scoured the ship and haven't found anything else.

[kittykat0510]

I think that's it. I got the achievement and I don't think I encountered anything secret other than those two areas.

[seancornball]

Thank you!