Sonic X Mega Man X

Sonic X Mega Man X  or Sonic vs. Rockman X: Battle for Nothing in Japan (ソニックvsロックマンX：何もない戦い, Sonikku vs Rokkuman'X: Nanimonai tatakai) is the arcade fighting game sequel to Sonic vs. Street Fighter. Instead of the Street Fighter cast, it is replaced with characters from the Mega Man X spin-off series.

Storyline
Takes place just a few months after the prequel. With Neo Metal Sonic defeated and the heroes returned to their own universes, the Uni-Bot Machine (athough damaged) is still functional and Dr. Eggman began repairing it after his creation fused with his invention. Meanwhile in Tails' House, Tails contacts Sonic to tell that a robot dragon is causing chaos to the Chao Garden, so Sonic reaches the place with his Sonic Speed and encounters him. After defeating him, the robot dragon introduces himself as Magma Dragoon and tells Sonic that Sigma is coming to his universe to conquer it and serves only for Reploids. Sonic, confused, heads to Tails and tells him what is a Reploid. After many researches, Tails reveals that Reploids are a high-advanced robots from th future and Sonic wonders that Eggman had finally conquered his future world, so he enters to another universe and was surrounded by Maverick Hunters X and Zero, who mistakes him for a Maverick. After some explanation to what's going on, Zero said that he saw a human with blue glasses and large mustache passing by, and Sonic knows that Eggman is here, it turns out that both the mustached scientist and Sigma worked together to merge both worlds into one with the upgraded Uni-Bot Machine. Now Sonic, X, Zero, and the other characters have to stop both villains and their plans once and for all.

Gameplay
The gameplay is pretty much the same as the original, and even brought back the Chaos Emerald mechanic, athough some of them where nerfed for competitive match.
 * Red: Increases Strength.
 * Green: Makes the fighter much faster.
 * Purple: Slows down your opponent.
 * Blue: Increases Defense.
 * Light Blue: Refill the Super Combo Gauce for a short period of time. Now lasts for 5 seconds.
 * Yellow: Slowly restores the player's health.
 * White: Adds Fire, Ice, or Electric attacks for each character.

Japanese

 * Jun'ichi Kanemaru - Sonic, Metal Sonic
 * Ryō Hirohashi - Tails
 * Nobutoshi Canna - Knuckles
 * Taeko Kawata - Amy Rose
 * Daisuke Ono - Silver, Green Biker Dude
 * Etsuko Kozakura - Cosmo
 * Mitsuo Iwata - Orbot
 * Wataru Takagi - Cubot, Infinity Mijinion
 * Mayumi Izuka - Bunnie Rabbot
 * Kenta Miyake - Vector
 * Kōji Yusa - Shadow
 * Yuuki Masuda - Espio
 * Taiten Kusunoki - E-123 Omega
 * Kōki Miyata - Grounder
 * Aoi Yuki - Sticks
 * Joji Nakata - Zavok
 * M・A・O - Eggrobo
 * Takahiro Sakurai - X
 * Ryōtarō Okiayu - Zero
 * Minami Takayama - Axl
 * Rumi Kasahara - Alia, Vanishing Gungaroo
 * Aya Endo - Iris
 * Yasuhiko Kawazu - Steel Massimo
 * Junichi Suwabe - Dynamo
 * Tsuneyoshi Iwatsuru - Dark Mantis
 * Hirotaka Suzuoki - Splash Warfly
 * Takashi Nagasako - Magma Dragoon, Spark Mandrill, Big the Cat
 * Mari Maruta - Split Mushroom
 * Shizuka Ito - Axle the Red
 * Ryuuzou Ishino - Chill Penguin
 * Nobuyuki Hiyama - Bubble Crab
 * Hideyuki Hori - Ninetails
 * Yumiko Kobayashi - Messenger Robo
 * Akio Otsuka - Red
 * Yasunori Matsumoto - Double
 * Norio Wakamoto - High-Max
 * Hiroshi Shimozaki - Vile
 * Kotaru Nakamura - Dr. Eggman, Eggman Nega
 * Makoto Terada (Mugihito) - Sigma

English

 * Roger Craig Smith - Sonic
 * Colleen Villard - Tails, Vanishing Gungaroo
 * Travis Willingham - Knuckles, Zavok
 * Cindy Robinson - Amy
 * Quinton Flynn - Silver
 * Amanda Leighton - Cosmo
 * Lauren Landa - Bunnie
 * Michelle Ruff - Cream
 * Kyle Herbert - Big the Cat
 * Vic Mignogna - E-123 Omega, Green Biker Dude
 * Nika Futterman - Sticks
 * Garry Chalk - Grounder
 * Kirk Thornton - Shadow, Orbot
 * Wally Wingert - Cubot
 * Matthew Mercer - Espio
 * Keith Silverstein - Vector, Infinity Mijinion
 * Microsoft Sam - Eggrobo
 * Ted Sroka - X
 * Johnny Young Bosch - Zero
 * Sean Michael Teague - Axl
 * Laura Bailey - Nicole
 * Erica Mendez - Alia
 * Kara Edwards - Split Mushroom
 * Jesse Merlin - Steel Massimo
 * Greg Chun - Ninetails
 * Monica Rial - Bokkun
 * Michelle Marie - Iris
 * Chris Guerrero - Red
 * Robbie Daymond - Dynamo
 * Scott McNeil - Chill Penguin
 * Yuri Lowenthal - Double
 * Christopher Corey Smith - Bubble Crab, High-Max
 * Rick Robertson - Spark Mandrill
 * Christopher Sabat - Magma Dragoon
 * David Wald - Dark Mantis
 * Chris Ayres - Spike Rosered
 * David Vincent - Vile, Splash Warfly
 * Mike Pollock - Dr. Eggman, Eggman Nega
 * Chris Tergliafera - Sigma

Trivia

 * This game is dedicated to Yuko Mizutani, the voice of Iris, who passed away in 2016 due to breast cancer.
 * They are some characters that where originally going to be playable, but where cut during development due to time constraits. These are:
 * Shadow (Mega Man X)
 * Berkana
 * Storm Eagle
 * Volt Catfish
 * Blast Hornet
 * Epsilon
 * Blaze the Cat
 * Orbot
 * Mecha Sonic
 * Tikal
 * Dark Oak
 * Robotnik from Sonic SatAM
 * Walter Naugus
 * Since Archie Comic's Worlds Unite never happened (thanks to Xander traveling back in time to the past and shot Sigma down, preventing him going to the Sonic world), this is Sonic and X's first meeting.