Instructions
Navigate to the character select screen and move the cursor so that it highlights "Ryu." Leave the cursor on Ryu for two to three seconds.
Move the cursor to highlight "T. Hawk." Leave the cursor on T. Hawk for two to three seconds.
Move the cursor to highlight "Guile." Leave the cursor on Guile for two to three seconds.
Move the cursor to highlight "Cammy." Leave the cursor on Cammy for two to three seconds.
Move the cursor back to highlight "Ryu." Leave the cursor on Ryu for two to three seconds.
Press the "Start" button and all three "Punch" buttons simultaneously to select "Akuma."