Revision as of 12:24, 9 June 2013

Game Mechanics

Movement speed

Luigi moves at different speeds depending on what setting he is in, whether he is running, and whether he is riding Yoshi:

• In a city:
  • Walking = 1 pixel/frame
  • Walking while riding Yoshi = 2 pixels/frame
  • Running = 3 pixels/frame
  • Running while riding Yoshi = 4 pixels/frame
• In Bowser's castle:
  • Walking = 1 pixel/frame
  • Running = 2 pixels/frame

Obviously, you should run as much as possible and get Yoshi as soon as possible in each city.

Except as noted under #Koopa stomping, you can change direction and switch between walking/running speed at any time, regardless of whether you are in the air.

Koopa stomping

After stomping a Koopa with an artifact (and only a Koopa with an artifact), Luigi is locked into his current horizontal velocity for 40 frames. This is the one case where Luigi does have momentum. This means that if you want to pick up the artifact dropped by a Koopa immediately after stomping it, it is best to let go of Y just before hitting a Koopa. You should only hit a Koopa while running if you actually want to keep going in your current direction and come back for the artifact after doing something else.

The game does not allow you to cross the street, enter a pipe, or open the Plumber's Toolbox during the post-stomp animation for the Koopa with an artifact. One of the animations takes a couple seconds to complete, so this should be taken into account when planning a route.

Stomping a Koopa that is not carrying an artifact does not affect Luigi's movement.

Pipes

There is a 7-pixel range in the middle of a pipe in which Luigi can enter. If Luigi is not in that range, holding down while on a pipe slides Luigi in the direction he is facing. Because of this, it is possible to fall off a pipe by holding down while standing in the wrong place. Luigi slides at whatever speed he would normally be walking/running.

Holding down+left or down+right slides Luigi in the held direction; however, Luigi cannot enter a pipe while either direction is held.

Street crossing layers

Luigi and the NPCs (including Koopas) have a Z-order in each street. When crossing the street, if an NPC is approaching that is "in Luigi's way," according to the Z-order, Luigi will wait for that NPC to pass by before crossing the street. It is sometimes necessary to stomp certain Koopas or adjust your movement in order to avoid having to wait.

NPC spawns

When Luigi enters a city, the game spawns each NPC near a "random" street crossing or pipe. However, the game uses a fixed seed for the spawn RNG, and it only updates it when entering a city. Therefore, the NPC spawns are really decided by the order in which you enter the cities.

Because of the effect on spawns, some city orders are noticeably faster than others. In the comments for the SDA run, __sdfg estimated that the route used in that run was about a minute faster than simply visiting the cities left-to-right on each floor.

NPC AI

NPCs move on a citywide timer. They pause while the Plumber's Toolbox is open and while the game is loading a new street or an information booth map, but in general, the NPCs are moving all the time. This movement must be taken into account when planning a route. It also means that completing an information booth quiz more slowly or quickly than usual can affect your actions later in the level.

Boss AI

A simplified version of the boss AI is as follows:

1. Run back and forth between the two walls.
2. If on the same pixel as Luigi, turn around and start a 60-frame countdown. If an earlier countdown is still active, ignore this and keep running.

Bosses sometimes turn around in other situations, but this is algorithm is close enough to form a strategy. The recommended approach is to stand a bit to the left of the door at the far right of the room and wait for the boss to come out. Just before the boss starts moving, jump to the left and hold Y so you have running speed. You should hit the boss, and the boss should eventually reach the same pixel as you and turn around. Move to the right a bit while the boss is running back toward the right wall, then jump to the left again so you hit the boss and the boss turns around again. Keep doing this until the boss is defeated. As long as you are moving left while the boss passes by Luigi and you don't get so close to the right wall that the 60-frame countdown interferes, you should be able to keep the boss from running off the left side of the screen. This saves several seconds versus letting the bosses just run back and forth. Check the SDA run to see this strategy in action.

If you get a low enough jump before hitting the boss, and you start turning back to the right soon enough after you hit, it is possible to bounce off the boss multiple times. This saves a second or two per hit. However, it is somewhat risky to try to get multiple hits because if you start moving to the right before the boss has turned around, the boss might get by Luigi without landing on the same pixel. In that case, the boss will continue running to the left side of the room and you will lose a lot of time.

All three bosses move at the same speed and take six hits.

Information booth menus

On the first floor of Bowser's castle, there is no randomness to which questions are asked at the information booths. As long as you visit the booths in the same order and you don't get any questions wrong, you will be asked the same questions in the same order every time. Therefore, you can and should memorize the button inputs for the menus on the first floor in addition to the answers. You can get through the menus a lot faster if you don't actually read them.

On the second and third floors, the questions can change from run to run. However, there are some restrictions on the questions that can be asked at each booth — the game doesn't really pick questions at random from the pool of three that it seems to have at each booth. It is sometimes possible to predict the second question based on the first one. Also, there are some cases where the first or second question you're asked can always be answered with the same button inputs. By learning these patterns, it is possible to skip reading some of the menu text on the later floors and save some more time.

TODO: create another page with all of the possible question orders and then link to it.

If you get a question wrong, the game prevents you from returning any artifacts for 15 seconds, so don't do it.

Input buffering

There are several cases where it is possible to save frames by buffering inputs:

• If you release the B button while in the air and then hold it again, you will jump immediately after landing.
• If you hold B while crossing the street or exiting a pipe, you will jump as soon as Luigi is able to move.
• In Bowser's castle, if you quarter-circle from left or right to up, Luigi will continue running in the same direction. When he passes in front of a door, he will enter it immediately. This does not work in cities: if you quarter-circle up in a city, Luigi simply stops.
• You can bring up the Plumber's Toolbox as soon as you enter a city by holding Start as Luigi comes out of the entrance pipe. You can do the same thing with pipes and street crossings later in the level if you need to change artifacts.
• In the Globulator, you can hold the direction you want Yoshi to travel at the next city he reaches.

Glitches

Broken button combinations

The game ignores certain buttons if other buttons are held. The behavior depends on whether Luigi is in Bowser's castle or in a city. Some of the button combinations that do not work as might be expected are listed below.

In a city:

In Bowser's castle:

The above effects should be taken into account to avoid losing time due to dropped inputs.

In the city stages, if you stop holding a button that prevents another button from registering, the game will act as if you pressed the other button. You can use this to work around the issue with the A button to some extent: hold Y+A while approaching an information booth and let go of Y to open the menu instead of letting go of Y and then pressing A. You still need to be careful to avoid hitting Y until after you have exited the menu, though.

High jumps

If you tap B for a single frame, Luigi will jump to the same height as his previous jump. If Luigi does not have a previous jump height, he will jump until he goes through the ceiling and then reappear on the ground. It is possible to stop Luigi from going through the ceiling by pressing B again while he is jumping.

This glitch is mainly documented to help people understand why it happens, as it can be triggered accidentally. The glitch has no known use in a speedrun. It may be triggered for cosmetic effect, however. See the very beginning of the SDA run for an example of this.

Jump heights are tracked separately in Bowser's castle and in cities, so if you would like to practice this glitch for some reason, you can reset your jump height by exiting and reentering a city.