Your goal in Blaster Master is to start in Area 1 and reach the final boss in Area 8. You are free to come and go through each of the areas as you please, but in order to access progressive areas, you must defeat the boss of an area and obtain an upgrade for SOPHIA. Each upgrade will enables you to overcome a blockade that prevents you from reaching the next area. Ultimately, you will have to travel through all eight areas in order to fully upgrade SOPHIA and access the final area.
The areas are not linear. Rather, they are connected in various ways. At times, you will need to backtrack through previous areas in order to access future areas. The chart below illustrates how each area is connected to the others, and can be used as a guide to figure out how you should progress through the game.
|Area 4||Area 5||Area 6|
|Area 1||Area 2||Area 3|
|Area 7||Area 8|