World 8 (Dr. Mario World)

World 8 is a cosmic-themed world in Dr. Mario World. Prior to playing a stage, Dr. Toad guides the player through a tutorial stage. The first area, or the first 20 stages give the player infinite hearts. Players start out with Dr. Mario, where players can obtain Dr. Peach or Dr. Bowser by stage 11. Players earn their first assistant, the Goomba, by Stage 20, as well as unlocking versus mode. When areas are cleared, Toads of different colors appear, including purple, yellow, blue, green, and red. In the second area, Dorrie also appears after clearing it.

The viruses featured in the regular stages are red, green and light-blue.

Area 1

Image	Stage	Overview
	Stage 281	This stage introduces keys, which float to the top of the stage until it collides with an object, and will not disappear until it comes into contact with a door. Viruses are hidden in most of the bricks.
	Stage 282	Instead of clearing all the viruses, the objective of this stage is to clear a path for the keys to reach the doors. The path is blocked by crates that each require four matches to clear.
	Stage 283	This stage features Lock Blocks, and Floatie Viruses that obstruct the path between the keys and the doors. Shells and since version 1.3.5, Exploders are available to help clear the path. Prior to version 1.3.5, the level layout was different. The following changes were made to reduce the difficulty of this level: Exploders are added directly above the keys Capsule count raised from 41 to 45 The virus on the top-left is changed to a Floatie Virus while the virus directly below it, originally a Floatie Virus, is changed to a regular virus Additional viruses are added directly above the bottom row of boxes
	Stage 284	This stage has a long column and row of yellow viruses, with the two other colors of virus to the left and right of the stage.
	Stage 285	This stage introduces Brick Blocks, blocks that are eliminated when an adjacent feature, such as viruses or pills, are destroyed.
	Stage 286	This stage orients viruses and brick blocks horizontally as opposed to the vertical orientation of Stage 5.
	Stage 287	The stage orients viruses in a less consistent manner than previous stages, which also introduces Empty Blocks mixed in as obstacles. Rainbow capsules can be obtained in this level due to the increased number of matches required to obtain one.
	Stage 288	This stage introduces shells as stage features, objects that can eliminate items horizontally when activated.
	Stage 289	A stage where players can first obtain a fully charged skill meter, which lets doctors perform a special ability specific to them. Dr. Toad also gives a free Capsule+ item prior to starting this stage.
	Stage 290	At this stage, players have access to the rest of the items prior to starting a stage, the Skill Up, Score+, and Random. When players complete this stage, they can choose to be either Dr. Mario, Dr. Peach, or Dr. Bowser. By clearing this stage, this area of the world map gets cleared from viruses.
	Stage 291	This stage introduces Skill Chargers, energy bottles that grant doctors a fully charged skill meter when activated.
	Stage 292	The second stage to have a Skill Charger, with viruses in more varied positions.
	Stage 293	Three colors of shells appear in this stage, which need to be individually activated to remove viruses horizontal of it.
	Stage 294	This stage features long rows and columns of viruses and brick blocks, with two shells on the upper left region.
	Stage 295	This stage introduces Exploders, bombs that destroy objects in tiles adjacent to them when activated.
	Stage 296	This stage has long rows of viruses and brick blocks, with two exploders that need only a half capsule to be activated.
	Stage 297	This stage introduces viruses hidden in brick blocks, which get revealed when the block is destroyed.
	Stage 298	This stage has Dr. Toad giving players a free hammer, a special item that enables players to destroy a single tile.
	Stage 299	This stage has Dr. Toad giving players a free Capsule Blaster, a special item that clears all capsules from the stage at once. The stage features both exploders and shells.
	Stage 300	The last stage of the first area, the stage has Dr. Toad giving players a free Skill Filler, a special item that fills up a doctor's skill meter. The stage has exploders and all viruses hidden in brick blocks. When cleared, the rest of the first area in the world map gets cleared of viruses. Additional data gets downloaded when the stage gets cleared, and players do not have infinite hearts past this point. Players also obtain their first assistant, and versus mode gets unlocked.

Area 2

Image	Stage	Overview
	Stage 301	This stage introduces viruses partially covered in ice, which require a match to remove and another to eliminate viruses.
	Stage 302	All viruses are either partially encased in ice or hidden in brick blocks in this stage.
	Stage 303	The center items in this stage are all partially encased in ice, including the shells.
	Stage 304	The stage is vertically-oriented, with viruses partially encased in ice and a Skill Charger on the upper area.
	Stage 305	This stage introduces the objective of finding coins in brick blocks rather than the main objective being to eliminate viruses. Upon completion of this stage, players have access to the timed challenge stages, starting with Stage 1A.
	Stage 306	This stage contains many viruses hidden in brick blocks.
	Stage 307	A long line of exploders are in the center of the stage, which then activates the shell on top of the exploder.
	Stage 308	This level contains viruses arranged in a triangle that are blocked off by fans, colorful crates and coins. The locked coins requires the top-most coins to be cleared before the next top-most coins will be unlocked, two at a time, with the two bottom-most coins being unlocked simultaneously when both remains. Prior to version 1.3.5, the level layout was different. The following changes were made to reduce the difficulty of this level: Capsule count raised from 39 to 44 Certain fans are encased in a layer of ice Players are guaranteed to start with a double rainbow capsule
	Stage 309	Much of the viruses are hidden in brick blocks, with players having access to skill chargers.
	Stage 310	The second stage that requires players to obtain coins from brick blocks. The stage additionally has two exploders.
	Stage 311	There is an exploder in the central part of the stage, as well as having the central row of viruses partially encased in ice.
	Stage 312	The stage has viruses hidden in brick blocks and partially encased in ice. Players can obtain the Skill Charger at the bottom early.
	Stage 313	The stage has long rows and columns of viruses, some partially encased in ice. The shell can activated early on the left part of the stage.
	Stage 314	The red shell on the left area of the stage can be activated early to destroy the ice on the viruses as well as destroy the row of viruses blocking the viruses on the right portion of the stage.
	Stage 315	The third stage where the objective is to find coins. It features a long column of blue viruses on the left and right parts of the stage.
	Stage 316	This stage has no blocks, with some viruses being partially encased in ice. The stage features an exploder on the center, which removes the ice on the adjacent viruses and eliminates the remaining viruses resulting from opening up the exploder.
	Stage 317	This stage has many viruses hidden in brick blocks. Viruses of the same color are found adjacent to the exploders on the stage.
	Stage 318	This stage features a large amount of exploders and viruses hidden in brick blocks. The exploders on the lower rows remove the ice covering the viruses, while the upper row exploders start a chain reaction, revealing viruses hidden in brick blocks.
	Stage 319	The upper portions of the stage have many viruses of the same color clustered together. The upper center viruses require that players earn the Skill Charger blocking to remove them.
	Stage 320	The final stage of the world represented by a castle introduces viruses coming downward when enough get eliminated. It is vertically-oriented and primarily features red and blue viruses. Once it is cleared, the remaining area of the stage map gets cleared of viruses, and players can access World 2. Upon completion, players earn a free ticket that lets them unlock either a new doctor, a new assistant, or leveling up an existing doctor or assistant.

Challenge stages

Image	Stage	Overview
	Stage 8A	Within an 80 second time limit, players need to eliminate all viruses. The stage is vertically oriented and it introduces pink viruses, which replace red viruses.
	Stage 8B	Within a 90 second time limit, players need to eliminate all viruses. The viruses form a circular shape on the center of the stage, with the inner-most viruses encased in ice.
	Stage 8C	Within a 90 second time limit, players need to eliminate all viruses. The viruses are more dotted across the stage with less regular patterns, with no blocks and some viruses being partially encased in ice. Players earn 1000 coins if they complete this stage.

Special Stage

Image	Stage	Overview
	Special Stage	This stage is split into four parts, with a row of viruses down the middle. Two parts are diagonally oriented and contain Brick Blocks, the other two have small spaces that the player must put half-capsules in. Red viruses are replaced with pink ones. Completing this stage awards the player 1000 coins, and as of Version 1.2.0, Dr. Toad is also awarded.