It is a port and revision of SimTower (1994), which Vivarium's predecessor OPeNBook developed, with some elements of its sequel Yoot Tower (1998).

The width is slowly expanded as Yama gets deregulation for the roads and buildings surrounding the player's Tower.

The site permits construction of a higher lobby at the ground floor, but doesn't permit the construction of building offices, condominiums, medical centers, security offices, nor recycling centers, allows up to 3 cinemas in the building (whereas the Office Building only allowed one), as well as a spa with water from a hot spring and hotel suites (once the appropriate star rating is reached).

As such, building built in this mode may resemble a mall-hotel hybrid, depending on the player's design.

Restrooms must be built; security must check the player's tower nightly; housekeeping cleans offices weekly, and cockroach infestation now has three phases: one (which requires a bug bomb), two (which requires a costly exterminator), and three (which condemns the infested facility).