The meat of Build-a-Lot is in Career Mode and the challenges that the local mayor issues to you at the start of each level. The first few objectives seamlessly serve as a tutorial for how to play the game where you learn about buying and selling property as well as building and upgrading houses. Moving on, the game introduces the player to the various special buildings like banks and workshops. These different buildings offer small sets of perks - banks allow you to earn interest on your money while the workshop allows you to train workers at a reduced price. These different building tools all go together to meet timed objectives such as "Reach $25,000 Monthly Income", "Own 4 Tudor Houses", etc. Casual Mode takes the same game play mechanics and removes objectives and timers in favor of a simple target dollar amount to accumulate.