Super Mario Bros.: The Lost Levels/Advanced Techniques

In Super Mario Bros., the only hidden secret that you would be required to face in order to continue the game is in World 8-4 (The one hidden coin block). This game is riddled with them! Sometimes the game might play dirty against you, and you will need to use a certain tactic to get through the area. The traditional way may cost you countless lives.

Expert Ducking

 * World 1-2 (Secret Area) - There is an overhang that will require you to either sacrifice your power-up or duck at the right point in order to get through. If you duck too early, you will fall into the crevasse.
 * Castle 3-4 - If you are super-sized in this maze, the correct route will be a tough squeeze, but this time you need to watch out for Podoboo. Run when you are successfully under the low ceilings, and duck when you see an opening. Otherwise, you may fall into Podoboo's pit.
 * World D-2 - If you are super-sized and you happen to try to dash underneath the final upside-down Piranha Plant, you will likely lose your power-up. Try jumping for the top and sinking down the pipe to the coin room.

Hidden Coin Blocks

 * World 1-2 (Secret Area) - There is a high mountain leading to Warp Zone 4. There are two hidden coin blocks that you need to uncover which are located above the pool of water. Don't move too far to the right or you will fall in.
 * World 2-2 - There are two hidden coin blocks that you will need to uncover in order to jump on top of the pipe and cross the huge pit.
 * Castle 3-4 - In part 2 of the maze, there are four hidden coin blocks that you need to uncover if you want to proceed through the second area.
 * World 5-1 - This level has two dirty secrets.
 * If you fall into the small landing right of the huge staircase, you need to uncover a hidden coin block to come back. It may be made harder by a 1-Up block.
 * If you choose not to climb to the Coin Heaven, you will need to uncover two hidden coin blocks to cross the mountain.
 * World 6-1 - You need to uncover a hidden coin block to jump over the Piranha Plant.
 * World 8-2 - Watch out for all of the hidden poisonous mushroom blocks in this level!
 * World 8-3 - This level has two dirty secrets.
 * Watch out for all of the hidden poisonous mushroom blocks in this level!
 * You will need to uncover a hidden coin block and a hidden poisonous mushroom block in order to jump onto the attached platform.
 * World D-3 - You will need to uncover a set of hidden coin blocks to ensure your safety.

Mystery Exit

 * World 3-1 - This level has three dirty secrets.
 * If you sink into the first pipe, you will end up travelling to a warp zone that leads you back to World 1.
 * If you take the Super Spring high over the flagpole and move too far to the right, you will end up at the very same warp zone!
 * If you sink into the second pipe, you will end up at the pipe blocked by a wall. You need to uncover a hidden power-up if you want to escape.
 * World 5-1 - This is not actually a bad secret (Unless you want to access World 9, or you want to Warp to Worlds 7 or 8). When you land after falling from the Coin Heaven, you will find yourself at a warp zone that takes you to World 6.
 * Castle 7-4 - This exit is fatal. If you run too far to the right on the ceiling after jumping on the five platforms, you will end up getting trapped until you run out of time.
 * World 8-1 - If you sink through the pipe in this area, you will be taken to a warp zone that leads you back to World 5.
 * World 8-2 - The flagpole is not located in the usual place! You need to climb a hidden vine to find it.
 * World 9-3 - If you don't jump over the ceiling and run over Bowser, it will be an incredible squeeze!
 * Castle C-4 - Just like Castle 7-4, you will need to avoid running too far to the right on the ceiling, or you will be trapped.

Traditional Jumps Don't Work!

 * Castle 2-4 — The beginning of the area has a narrow and tough landing for a super-sized hero. If you try to land the traditional way, you have a 50% chance of falling into the lava pit.
 * Castle 4-4 — You will need to do it at least once after you pass the Hammer Brother. If you are already Super Mario, you will need to make sure that you stop at the right time. Don't stop too soon, or you may get scorched by Bowser's fiery spit.
 * Castle 8-4 — This level has two dirty secrets.
 * In the beginning, you will need to make a backwards jump to land on the floor below the staircase.
 * Danger: If you are super-sized, you need to rely on luck because there is nothing to downsize you!
 * In the third area, if you are super-sized, you will need to jump and land properly to proceed onto the fourth area.
 * Castle D-4 — Much like the beginning of Castle 2-4, you will need to make a skilled landing to avoid falling into the lava pit.

If you are playing as super-sized Luigi, the lack of friction means it is harder to land. You may have to sacrifice your power-up to land safely. Regular-sized Luigi (and Mario) will always land safely after dashing.

Good Timing

 * World 4-3 - You need to successfully jump from the right attached platform and land on the higher mountain head if you don't want to rely on luck. If you hit the bottom, the gap is too wide, and you need to rely on the luck of flying Bullet Bills.
 * World 8-3 - After you uncover the two hidden coin blocks you need to jump onto the attached platform, you will need to wait for the right to elevate very high (but not too high) so that you can successfully jump the wide gap between the platform and the floating blocks just before the flagpole.

Trust Parakoopa

 * World 4-3 - One of the huge gaps is made accessible by a red Parakoopa. You need to stand close to the edge in order for it to appear. Run back, then dash and jump!
 * World 8-1 - You will need to stand close to the edge and wait for the red Parakoopa. This is made harder by both the Piranha Plant to your left and the crevasses in the floor.
 * World B-3 - Near the end, at the very huge gap, you will need to wait for a green Parakoopa to fly towards you so that you can jump.
 * World C-1 - At one point, you will need to wait for a green Parakoopa.
 * World C-2 - You will need to stand close to the edge in order to trust jumping on the red Parakoopa.

Move Right, Then Left

 * World D-3 - Stand on the final lonely Bullet Bill launcher, wait for the Hammer Brother, then jump over him. Do the same on the set of three bricks.
 * Castle D-4 - Between the staircase in the surface area and the pipe where you need to land, move a little slower on the staircase so that you don't accidentally jump on top of a Piranha Plant.

Miscellaneous

 * Castle 8-4 - In the fifth area, don't fall down to the lowest pipe! You will be blocked by two hidden coin blocks and will have to warp back to part 1.
 * Castle C-4 - One of the fire-bars can be incredibly difficult. It's nearly impossible to avoid the fire-bar enclosed by two bricks. You will need to dash quickly, or you will get burned.
 * World D-1 - Probably a really dirty tactic against you, there are two Hammer Brothers at the beginning that may force you to rely on pure luck. Otherwise, you can dash very quickly and jump on the lower Hammer Brother.