Front Door

The Front Door is a level in Super Mario World. It can be accessed by the completion of #7 Larry's Castle, or through the Star Road connected from Star World 5 and Valley of Bowser 4’s secret exit. It consists of Bowser's Castle in Dinosaur Land. This level and the Back Door are both counted as the same exit, and as such, the player is only required to complete one of them to achieve 100% completion.

Layout
Inside is a bright hallway with four doors – four areas (numbered 1 to 4) for Mario or Luigi to choose from, each door leads to a different area with enemies and obstacles that vary depending on which door was selected. All four areas then lead to a second bright hallway with another four doors-four more areas (but this time numbered 5 to 8). The obstacles and enemies will again vary on what door is selected. The last four areas lead to a dark room and a red ? Block that activates a spotlight at the top of the screen; this room is also seen at the beginning of Back Door, with slight alterations. This area has Mechakoopas. The area is also the only area in the game where the player can encounter Ninjis. The boss door is found at the end.
 * Door 1: An auto-scrolling room with Pillars (as previously seen in #1 Iggy's Castle and the Forest Fortress), Lava Bubbles, and Yellow, Green, Red, and Blue ! Blocks to stop the player from falling into the lava.
 * Door 2: A series of fences with Climbing Koopas, a pit filled with spikes and flying Lava Bubbles.
 * Door 3: A maze with many blocks and Mechakoopas. A 1-Up Mushroom and Cape Feather are hidden in the room.
 * Door 4: A room full of floating platforms with Lil Sparkies and a Hothead.
 * Door 5: A room filled with Skewers and Thwomps. The player must sprint past these at the right time in order to get through unharmed.
 * Door 6: An underwater room with Dry Bones that throw bones at the player, Fishbones, Ball 'N' Chains, and spikes.
 * Door 7: A room full of Gray Bowser Statues that shoot fireballs and Gold Bowser Statues that pursue Mario/Luigi.
 * Door 8: A room with Chargin' Chucks that jump at the player.

Boss battle
Beyond the boss door is the roof of the castle, where the player must fight Bowser in his Koopa Clown Car. If Mario or Luigi touches the propeller at the bottom of the Koopa Clown Car, he will take damage; otherwise, he will simply bounce off. In the first stage of the battle, Bowser will fly around the top of the screen, throwing Mechakoopas. The player must grab and throw these upward at Bowser - if they hit the Koopa Clown Car, they are destroyed. After taking two hits, Bowser will fly off-screen to drop many Flames from the sky, before returning to fight. Princess Toadstool will throw a Super Mushroom to her left. The player may choose whether to take it or not.

In the second phase, Bowser will then try to hover above Mario or Luigi and drop Big Steelies on them. After throwing two Big Steelies, he will throw two Mechakoopas. Again, the player must kick the Mechakoopas up toward Bowser and hit him twice. After another round of Flames (and another Super Mushroom), Bowser and the Koopa Clown Car will start bouncing on the ground, trying to crush Mario or Luigi. Eventually, more Mechakoopas are thrown and the player must again kick two into Bowser, defeating him.

A message comes up as Peach kisses Mario (or Luigi): "Mario's (Luigi's) adventure is over. Mario (Luigi), Peach, Yoshi and friends are all going to take a vacation." Four groups of fireworks appear, with the last one being heart-shaped. The screen then begins to show the credits (with Mario walking and Peach riding Yoshi, as the seven Yoshi Eggs follow along) and the list of enemies from the game, complete with pictures and name tags. After the enemy gallery, a picture of Mario, Luigi and Peach with text reading “The End” will fade in. In the SNES version, the screen will freeze on the image once the music finishes and the system will need to be turned off or reset. In the GBA version, a custom illustration is added to the image, and the player can return to the Yoshi's Island world map upon pressing, alongside being able to save the game.

On a side note, while the HUD is absent in the SNES version of the final battle, the Item Stock still appears if it is holding a power-up; in Super Mario Advance 2, the HUD (and thus, the timer) is present.

Trivia

 * If Super Mario Advance 2 is played on a backlit Nintendo handheld (such as a Game Boy Advance SP or Nintendo DS Lite), the background in the dark section of the level is so bright that the red ? Block's light is not entirely needed to see where the player is.
 * A room in "Send in the Clown" seems to be the Front Door, due to similar background designs, with the same white and green lozenge curtains and a block that gives light, along with the boss fight. However, the light block is the normal yellow color instead of red, and the spotlight is replaced with torch lamps.