Dr. Mario World was a free-to-play tile-matching puzzle game developed by Nintendo EPD (in conjunction with LINE and NHN) and released by Nintendo for iOS and Android devices on July 9, 2019. It was later discontinued on November 1, 2021.
A mobile-focused spin-off of the Dr. Mario series, Dr. Mario World changes its puzzle formula for use with touchscreen devices. Like other free-to-play mobile puzzle games, the game made use of an overworld where players can continue their progress (or revisit previous stages to improve their score) at their own pace.
Similar to its source, players attempt to clear their playfield of multi-colored Viruses by positioning multi-colored Capsules in a way to create a row or column of three (or more) of the same color. Unlike the traditional Dr. Mario game, Capsules "float" from the bottom, and players can manipulate one or more active Capsules by dragging and tapping them. While some stages are timed with unlimited Capsules, most of them give players an unlimited amount of time to determine what to do with a limited amount of Capsules. Score is determined wither by the amount of Capsules/Time remaining.
The game also introduced power-ups, special character-based abilities, and new obstacles that either help players (such as Shells and Exploders) or make the game more challenging (such as Blocks, shielded Viruses, and hidden Viruses). In addition to the single-player Stage Mode, the game also had a separate Versus Mode for 1v1 online multiplayer, including ranked play with special rewards.
As a modern free-to-play mobile game, the game used multiple in-game currencies (Coins and Diamonds, the latter of which can only be bought with real money) for continuing stages, acquiring power-ups, and unlocking new characters (the latter through a gacha system). The game's Stage Mode also had a restrictive lives system, where players must use one of their limited amount of Hearts to start a level and can only replenish them either by completing a level (for one Heart), by waiting in real-life (one Heart per 30 minutes), or by using Diamonds (for fully replenishing them, with a special offer for an hour-long unlimited play).
Players can choose from one of several playable Doctors, each with their own special ability that can be activated once they fill up their Skill Meter. Some characters have separate abilities for Versus Mode, while all characters can upgrade their Versus Mode skill through gacha (by acquiring multiple copies of the same Doctor from Staffing).
Each Doctor also have different attacking properties in Versus Mode, with some characters (such as Bowser) sending more Viruses with more reliably (at the cost of sending them less often).
At the very beginning of the game, players play as Dr. Mario. After a short time, though, they choose between Dr. Mario, Dr. Bowser, and Dr. Peach and can unlock the rest through Staffing (with additional ones added post-release).