As is well documented, the game has 8 maps that are repeated indefinitely with increasingly difficult levels of difficulty. Each map takes up 672 ($2A0) bytes from B3B0 to C610 inclusive, and simply consists of 21 sets of lines of 32 characters, arranged from the bottom of the screen to the top.

Each byte contains a UDG ID. This is multipled by 8 and added to 84F0, which contains the graphic to draw.