For the first year, the full game required a subscription; free accounts could only access to a portion of the content. It was originally scheduled to be released in summer 2008, but the release date was pushed back to January 14, 2009. The game became free-to-play on April 19, 2010.
Planet Fusion, ruled by the evil Fuse, has traveled throughout the galaxy for millennia, devastating countless planets and civilizations. Earth is its next stop. The player joins forces with the characters from various Cartoon Network series to beat this threat.
The game begins with the player character participating in Dexter's time traveling experiment. As Dexter starts up the machine, Dee Dee, Dexter's sister, sneaks in and messes with the controls using her famous line "Ooh what does this button do?". This causes a time-jump error, sending the player much further into the future than Dexter intended, where they arrive in the midst of a war between the Fusions and Cartoon Network's characters, where it is evident that the Fusions are winning. This section of the game serves as a tutorial, introducing the player to the controls and types of items in the game. After completing an optional training level, players are tasked with repairing Dexter's time machine to return to the present. Upon gaining four Nanos and completing a number of key missions, the time machine is considered fixed and the player can return to the present for the main portion of the game.
Characters from various original Cartoon Network shows appear in the game, redesigned in an anime style by Foo Midori. In addition, small, miniaturized versions of Cartoon Network characters called Nanos are collected along the way and travel with players, providing powers and abilities to assist during missions.
In FusionFall, the player takes control of a customized avatar. Their character is viewed from a third-person perspective, and the range of movement consists of walking in any direction and a huge-distance jump. The game has large playable environments, with travel facilitated by various glitch points. Gameplay primarily focuses accomplishing missions to take you a step closer to saving the Cartoon Network Universe. The player is provided with various weapons to accomplish this, including ranged and melee weapons. Unlike ordinary role-playing games, the player does not gain experience in the conventional sense. Instead, they gather a loose analog known as fusion matter (which has multiple purposes) through defeating enemies and completing missions, and upon collecting enough can perform a mission to raise their level. The player is guided in their quest by a specific character, beginning with Dexter's computer, Computress. After leaving the first level, they can choose between a wider range of guides and can switch between these guides at their discretion for a small fee.
The main focus of the game is the completion of missions. Missions are given by various characters (for example, Numbuh 5 of Codename: Kids Next Door and Ben Tennyson of the Ben 10 series) around the game world, who usually cluster around travel hubs. Missions come in three types: Nano missions, Guide missions, and World missions. Nano missions are granted automatically once the player gathers enough fusion matter. A meter encircling the minimap shows the player's progress in this regard. Guide missions are special tasks done on the behalf of the guide character, typically offering the best equipment available as a reward. World missions are generic tasks which offer lesser rewards, but are far more numerous to compensate. Unlike the first two types of missions, which can only be done one at a time, the player can run four different World missions concurrently.
The key to progressing in the game is the collection of Nanos, thirty-six (so far, more will be added) miniaturized versions of Cartoon Network characters which serve as allies in combat. The player's level is tied to the number of Nanos they have collected (e.g. a player at level 6 will have six Nanos). Nanos are obtained during Nano missions, in which the player must defeat an evil Fusion doppelganger of a Cartoon Network character. A Nano (usually of that character or a related entity) is granted to the player upon the doppelganger's defeat. Once obtained, players can choose between one of three abilities for the Nano. The chosen ability can be changed later for a fee. Nanos grant a wide range of abilities depending on the specific Nano, ranging from increasing the player's performance (run speed, jump height, etc.) to special attacks (stunning moves, area-effect damage, etc.), as well as a number of player-cooperative abilities in the same vein. Players are limited to carrying three Nanos at a time, which can be switched out at Nano stations. Once activated, Nanos will aid the player until they are put away or tire out, at which point they will vanish in order to regain their strength.
In terms of difficultly, a solo player can progress in the game without much trouble. Enemies in any given mission will usually be within the player's ability to defeat, though it is possible to be overwhelmed by sheer force of numbers. So long as the player isn't under attack, their health will regenerate fairly quickly, eliminating the need to replenish health between missions. If the player passes out, they are revived at a nearby respawn point, called a "Resurrect 'Em", the only penalty being a moderate drain of the energy of the player's Nanos. While solo play is made possible, players can group together to tackle tougher enemies, sharing the rewards from victory.
The game world varies between open and closed arenas. For the most part, missions take place on the surface with the other players. Enemies on the surface respawn quickly and are spread out over large areas, thus making sure that even a large number of players performing the same mission can complete it in a timely fashion without having to wait for their targets to appear. There are also sealed-off areas called Infected Zones that mix elements of platforming with an abundance of dangerous enemies. These areas contain one or more Fusion lairs, the end point of Nano missions and certain regular missions. When entering a Fusion lair, players are spawned into an isolated dungeon, preventing others from interfering (grouped players can enter lairs together).
The open beta testing began on November 14, 2008, available to anyone with an account on Cartoon Network's website. It ended on November 16, 2008. A second beta began on December 5, 2008, and ended on December 7, 2008. The third took place during the weekend of December 12, 2008, with a single-day extension on December 19. A final beta test started on December 27, 2008, and ran until January 11, 2009. All characters created before December 22, 2008, including those of the FusionFall staff, were deleted, but all made on or after December 27, 2008, were carried onto the official release.
When it was first released, FusionFall required a paid subscription for the full game, with a limited portion of the content available to free accounts. Free accounts could only play in the "future" portion of the game, which only allows players to collect four Nanos and create two characters. The full game has a total of 36 Nanos to earn and allows players to create up to four characters. Players with characters that progressed into the past during the sneak peek or during a previous subscription had their characters locked until a current subscription was purchased.
Subscription plans included one-month, three-month, year-long, and family plans. The FusionFall Victory Pack Exclusive was made available for purchase when the game was released. It contained a four-month subscription, as well as a game guide, T-shirt (if bought from GameStop), and exclusive outfits and weapons for the player's character. The Victory Packs were eventually discontinued, having been replaced with one-month and three-month game card available for purchase at Target outlets.
The game was made completely free on April 19, 2010.
A manga prequel, co-written by Matthew Schwartz and Megas XLR co-creator George Krstic, entitled FusionFall: Worlds Collide!!, was passed out during Comic Con '07. Due to the overwhelming success of the manga, George Krstic is in talks to write a script for a FusionFall feature based on the manga to accompany the game's launch. The comic is currently available on the official website for public viewing and in PDF format for download. It covers the events leading up to the start of the game.
Occasionally on certain holidays such as Thanksgiving or Christmas, Fusionfall has a small in-game celebration that usually has a special code for a holiday item, holiday scenery, exclusive items, and missions carried by special guest appearances of future cast members, such as Chowder or V. V Argost. Events for holidays stretch from 2 weeks to several months. Some roll directly from one to the other. Other events Fusionfall is now experimenting with are Fusionfall Adventures, special events with new items, NPCs, missions, and dungeons for their newest shows such Ben 10: Ultimate Alien, Adventure Time, and Generator Rex. Also, a special year-long event in 2010 gives out a new code item every week, the code lasting for two weeks.
The following voice actors have done voice work in this game:
- Maxwell Atoms - Jeff the Spider
- Diedrich Bader - Hoss Delgado, Fiskerton
- Dee Bradley Baker - Numbuh 4, Toilenator, Swampfire, Humongousaur, Echo Echo
- Greg Baldwin - Nano Aku
- Kathleen Barr - Marie Kanker
- Jeff Bennett - Ace, Johnny Bravo, Azmuth
- Steven Blum - Vilgax, T.O.M.
- Corey Burton - V.V. Argost
- Catherine Cavadini - Blossom
- Greg Cipes - Kevin Levin
- Kathryn Cressida - Dee Dee
- Jim Cummings - Fuzzy Lumpkins
- Elizabeth Daily - Buttercup
- Eddie Deezen - Mandark
- Grey DeLisle - Frances "Frankie" Foster, Mandy
- David DeLuise - Coop
- John DiMaggio - The Scotsman, Shnitzel, Jake, Bobo Haha
- Benjamin Diskin - Numbuh 1, Numbuh 2
- Greg Eagles - The Grim Reaper
- Paul Eiding - Grandpa Max Tennyson
- Dave Fennoy - Tetrax Shard
- Keith Ferguson - Blooregard Q. Kazoo
- Erin Fitzgerald - May Kanker
- Marty Grabstein - Courage
- C.H. Greenblatt - Fred Fredburger
- Jennifer Hale - Princess Morbucks
- Mark Hamill - Stickybeard
- Matt Hill - Ed
- Howard Hoffman - The Chickens From Outer Space
- Richard Steven Horvitz - Billy
- Roger L. Jackson - Mojo Jojo
- Janyse Jaud - Lee Kanker
- Ashley Johnson - Gwen Tennyson
- Nicky Jones - Chowder
- Tom Kane - Professor Utonium, Him, Mr. Herriman
- Tom Kenny - Eduardo, The Mayor of Townsville, Ice King
- Wally Kurth - Agent Six
- Maurice LaMarche - Father
- Phil LaMarr - Samurai Jack, Wilt, Dracula
- Sam Lerner - Zak Saturday
- Yuri Lowenthal - Ben Tennyson, Albedo's Ben Tennyson Form
- Sean Marquette - Mac
- David McCallum - Paradox
- Richard McGonagle - Four Arms
- Lara Jill Miller - Juniper Lee
- Candi Milo - Dexter, Coco, Cheese
- Phil Morris - Solomon "Doc" Saturday
- Rob Paulsen - Major Glory
- Khary Payton - Hex
- Vyvan Pham - Ship
- Kevin Michael Richardson - Demongo
- Zeno Robinson - Alan Albright
- Daryl Sabara - Rex
- Tony Sampson - Eddy
- Dwight Schultz - Thromnambular
- Jeremy Shada - Finn
- Kath Soucie - Computer
- Tara Strong - Bubbles
- Nicole Sullivan - Drew Saturday
- Cree Summer - Numbuh 5
- Fred Tatasciore - Zon
- Lauren Tom - Numbuh 3
- Thurop Van-Orman - Flapjack
- Samuel Vincent - Edd
- Hynden Walch - Princess Bubblegum
So far the most powerful players in rank is White The Ghost at number one, Razor Fang at number two and Eagle Shadowlink as number 3.