The first floor is open to the public, displaying portraits of Altru's three presidents. It also displays numerous artifacts relating to the company, among these are old oil-prospecting tools and a model of the Altru Tower from its announcement event three years prior. However, on the day that Altru Tower was completed, the workers were booted out, causing an outrage. Team Dim Sun had commandeered the building for its own use, forcing the player to break in and force the team out.
The building consists of ten floors, though only the first, ninth and tenth are seen in the game. When the elevator on the first floor is entered for the first time, the player must deduce Isaac's password, and after doing so, will be en route to the ninth floor when the elevator stops and Team Dim Sun attacks. From there, the player must enter the elevator shaft and reach the ninth floor manually through an air duct.
On the ninth floor, the control room for the Incredible Machine can be found. It is also where the Yellow Gem is stored. Also on the ninth floor are several research rooms, a trash dump and a restroom.
On the Altru Building's roof is the entrance to Altru Tower.