Use this trick to see one of the best endings the easy way. Enable the Harder Game mode, then set Difficulty to One Star and beat the game.
Hold L + R on both controllers during the start screen and you will see the character profiles one by one.
No Special Techniques
Turn on the game. When the Capcom logo appears, quickly press Down, R, Up, L, Y, B. You'll hear a chime if the code worked. When you begin a one-player game, you'll notice that all of your Special Techniques have been disabled!
Fireball: DOWN, FORWARD, PUNCH
Super Fireball: BACK, DOWN, FORWARD, PUNCH
Spin Kick: DOWN, BACK, KICK
Turn on the game and wait for the screen that shows the Street Fighter II logo in the background against a black screen. When this appears, quickly press Down, R, Up, L, Y, B on Controller Two. You must complete this code as the second screen showing the giant Turbo logo appears. You'll hear a chime if the code worked. At the Title Screen, you'll have the option of raising the Turbo speed up as high as ten stars! Go for it!