Toaru Majutsu to Kagaku no Puzzdex

Toaru Majutsu to Kagaku no Puzzdex (とある魔術と科学の 謎解目録 (パズデックス) ), translated as A Certain Magical and Scientific Puzzdex, is an action puzzle video game for iOS devices, Android devices, and mobile phones, featuring characters from both Toaru Majutsu no Index and Toaru Kagaku no Railgun. It was planned to be released in February 2014 for Android devices and March for iOS devices, though it was later moved to an unknown time. Service was concluded on June 30th 2016.

Gameplay
The gameplay looks similar to , where game is split-screen, with a role-playing game at the top where the player apparently gets to fight other chibi-fied characters from the series. There would also be character cards reminiscent of Toaru Majutsu no Index Struggle Battle. The game uses chibi-fied version of the characters from the series. Teams of characters can be formed and a copy of the character with a different color scheme can be found if the opponent already has that character in their team. Bonuses, known as "Party Skills" can be formed depending on the characters used in the party. These bonuses increase either damage or health by given percentage, depending on the number of characters involved. For example, having a team consisting of four or more characters from Toaru Kagaku no Railgun increases damage by 4%, while having in team all three Delta Force members increases health by 3%.

The objective of this game is to move a selected tile across the board in order to form horizontal or vertical chains of three or more gems of the same type. Once a tile is selected, it can be moved in any direction for about 3-4 seconds after first movement. Tiles disappear when chains are formed and characters with matching color scheme then attack the opponent. The gaps that are created by disappeared tiles are filled in by gems falling from top, which can sometimes trigger additional chain reactions. The damage on the opponent is directly proportional to the number of chains and character's damage. There are 5 types of tiles but sometimes special tiles appear on the screen. Defeating an opponent allows the player to gain experience. Health bars appear next to a character and they are depleted when they take damage. The game uses stages based on locations from the series. Like an RPG, entering a stage drains player's stamina, which is refilled after some time has elapsed, player has increased his rank or after using special items.

As it is a social game there are also events that allow the player to compete with others as well as raid boss fighting with cooperation with other players. Players can also have other players' characters in their own party and exchange gift items. Rankings of the players are also present.

Event Stages
Apart from the regular stages, there are also special event stages, some that are only available for a certain amount of time. Examples of this are stages that increases a particular attribute of the characters occur during the stage, strengthening stages that allows for better experience gain, and Cosplay Stages that incorporates the "charm" of the female characters. This forces the player to organize their team wisely.

New events were usually released either at the beginning/end or around the middle of every month following the game's release, up to mid-December 2015, and usually held over a two week period.

Utopia Stage
When the favoribiity of a character increases, it will be released to the "Utopia Stage" for playing by touching the screen as a special reward, sexy card illustrations drawn from the series of the character. Favoribility of a character is increased by having the specified character in team and completing certain stages with them.

Heavy Object
Heavy Object characters Milinda Brantini and Froleytia Capistrano also appear in the game, available during a collaboration event to promote the recently announced Heavy Object anime until October 19th 2014.

Other
As part of a crossover event with Sword Art Online and Mahouka Koukou No Rettousei, characters from the two series were featured in the game.