Zack is finally found before the final stage of the game, within the annex (storage building) at the far left of the island. You will need to recover the two missing parts to finish building his Mech walker, then enter and defeat the monster plants within the annex.
There are no windows that open inward on Steamworks Island. There is a skylight in the City Hall that can be opened with the Multi-Tool. You go out the hatch above Zack's room in the living quarters, to reach the Mech Crank on the vines.
You find the pie.
you throw your computer because it frustrstes you so much...
its in the museum on mainstreet of steamworks island :)
It is on the counter beside spocket.
You might find a drawbridge in the harbour.
It's Steamworks Island #14th Island
steamworks island my friend! :D
(The solution is at the related question "How do you beat Steamworks Island")
You find the dirty beaker inside the Steamworks Museum when you go all the way to the top right side.
the crab on steamworks island is next to the living quarters
You go to Steamworks and head to the museum and there is the Deogen