Front Door is a level in Super Mario World. It is Bowser's Castle in Dinosaur Land. Inside is a bright hallway with four Doors numbered 1 to 4. Each door leads to a different room with enemies and obstacles that vary depending on which door was selected.
1. Giant wooden pillars and scroller level, with each of Yellow, Green, Red, and Blue ! Blocks to help you against the lava. 2. Fences and flying Podoboos (Considered the easiest). 3. Maze with many blocks, Koopas. 4. Lil' Sparky's and Hotheads.
All four rooms then lead to another bright hallway with another four doors, this time numbered 5 to 8. The enemies and obstacles will again vary depending on which door is selected.
5. Obstacles with thorns and Thwomps. 6. Water, Dry Bones that throw bones at you, spikes and Bony Beetles. 7. Bowser statue's flames, Bowser's statues that jump at you. 8. Chargin' Chucks that jump at you.
After the second set of doors, the player will find a dark room and a red block that activate a light at the top of the screen. This is slightly different than the room you will see at the beginning of Back Door. This area has Mecha Koopas, the boss door at the end, and is the only area in the game where the player can encounter Ninjis.
Beyond the boss door is the roof of the castle, where the player must fight Bowser in his Koopa Clown Car. In the first stage of the battle, Bowser will fly around the top of the screen, throwing Mecha Koopas. The player must kick these upward toward the Koopa Clown Car. After taking 2 hits, the Koopa Clown Car will fly off-screen, and a bunch of fireballs and the Koopa Clown Car will return. Princess Toadstool will throw a Mushroom to her left. You may choose whether to take it or not. Bowser regains conscience and goes back on the top of the Koopa Clown Car, and this time, it will then try to hover above the player, and drop Big Steelys on Mario . However, one out of every three times something is dropped, it will be two Mecha Koopas. Again, the player must kick the Mecha Koopas up toward Bowser, and hit him twice. After another round of fireballs (and another Mushroom), Bowser and the Koopa Clown Car will start bouncing on the ground, trying to land on Mario. Eventually, more Mecha Koopas are thrown and the player must again kick one into Bowser, defeating him. Several fireworks appear (four times), the last one being heart shaped, as Peach kisses Mario (or Luigi). A message comes up; "Mario's(or Luigi's) adventure is over. Mario(or Luigi), Peach, Yoshi and friends are all going to take a vacation." The screen then begins to show the credits and monsters.