Do You Need All the Vessels to Complete the Game?

[Pacific PR01]

I've found 4 of them, and Tess is telling me I now have enough power and to go and destroy the water clock in the attic. But when I go up there I can't seem to do anything beyond place the existing vessels and have Tess warn me about Duncan. The achievement for getting all the vessels has a lower percentage than the ones for beating the final boss, so are they just needed for the good ending?

[[OSM]7point62]

You need all the major vessels in order to open all the doors which are "locked by powerful magic" (eg; all the colored vessels). You do not need any of the 4 white vessels, which only serve to refill the powers of the other ones. But in short you're not getting to the main attic, or any of the tower attics, until you have all the colored vessels. You'll see where to put them once you have the master bedroom unlocked -- and yes, you can still use their powers as if they were still in your inventory, even after you place them around the alter.

I'm not sure why you got that message; I assume it was from one of the FMV sequences? Maybe you made it to a late-game area early and the message wasn't intended to be seen because most people wouldn't get there til they already had the others? Not sure, but the thing with KT being a pseudo-open world game is that other than a handful of specific doors you can explore the entire island and complete most areas and collect vessels in any order. Including running, say, all the way out to the lighthouse or something right from the docks.

[Pacific PR01]

Thanks for the reply, it is the FMV sequence right outside the master bedroom (with the portraits) that I unlocked after getting all the keys. I've been doing a blind playthrough and thought I'd been thorough, but seems like I'm only halfway there.

[Dr. Basement]

The achievement description is confusing for "Canopic Collector," but it actually requires you to get all colored vessels AND the white vessels for the achievement, but only the colored ones are required to access the attic and to unlock the color wheel doors.

[SecretAgentKiiN 特务健]

Maybe you need some hints? You can try this:
https://steamcommunity.com/sharedfiles/filedetails/?id=3351338203