Super Mario Bros.: The Lost Levels/World 4

World 4-1

New persistent red Piranha Plants and a flying Lakitu welcome you to a very challenging world. Be careful!
From this point to World 5, you can only go forward. Green Piranha Plants are history.
It's not shown in the picture however directly adjacent left above of the blocks with the multi-coin brick in the middle is a hidden coin block.

You'll have to hit the spring at the start of this section while running at super speed in order to clear the long gap ahead.
It's not shown in the picture however directly adjacent to the staircase is a hidden one-up block.

When you pop up the Power-Up Mushroom, wait for it to slide off the block, then catch it in the air.
The first pipe of this section leads to a challenging, Coin-filled swimming area A. Swim at your own risk.
The last block before the staircase contains a vine which leads to another coin heaven A.
Immediately to the right of the staircase, make two hidden Coin Blocks appear for extra running room on your leap to the flag.

This level is a source of infinite lives because the coin heaven transfers you back to the staircase after the large pool of water. You have the potential to collect 123 coins per loop.
- If you want to try and speed things up, you can try looping with just the coin heaven. You collect only 83 coins per loop, but you might move a little faster this way.

When you pop up the Power-Up Mushroom, move to the right, then wait for it to drop. The Bullet Bills will not hit your hero.
Grab the Starman in the first brick after the cannons, and dash. You'll flatten all of the Mushroom World enemies in your path with ease.

If you're trying to get a Mushroom, be sure to collect it before you hit the final "?" Block, or you'll replace it with a Poison Mushroom.

The platforms in this area start to drop upon contact. Jump quickly to avoid falling. The 2nd, 5th and 6th lifts move horizontally.
In Vs. Super Mario Bros, however there are 2 small platforms to land below the lifts. Also since this is level 6-3 in Vs. Super Mario Bros, the lifts are narrower and it’s night and grey.

Bounce off of the back of the Koopa Paratroopa near the right side of the first long gap to guarantee a safe landing.
A Bullet Bill flies through this area. Get out of its way and keep moving.

It's difficult to stop on the one-block platforms at the very end of this level. You may have more luck with quick hops.

Collect the power-up at the beginning of this world, but don't put yourself at risk of being burned by the fire-bar to get it.
If you want to get past the beginning gap, go back and run.

Three Koopas drop into the low-ceiling passage at the start of this section. Duck and jump to stomp them, but watch out for the rebound shell.
If you're controlling Mario, you'll have to dash and jump to reach the dangerous Fire-Bar block at the beginning of the section. Hop on, hop off, and run.
Be careful when you reach the lowering platform. As small Mario, use your super speed dash while pushing Right to reach safety. Super Mario must jump from lower down.
Run through the middle passage at the end of this section and pop up the Power-Up Mushroom. Then drop and run to catch it.

You'll have the most luck in your encounter with the king if you dash under him as he jumps.