Like I said, most of the switches are not suppose to make any sense, but since there are restless people who wouldn't give up on that fact, I made up explanations..
Why the switch?.. and other questions...

I was trying to achieve a pattern of switching so that I could challenge myself both my versatility as an artist and as a crackhead fangirl. My goal is that every game is a different fandom or show and characters of one show must only portray characters from the certain game switched with it. and I also based these fandom-game switching on similar cartooning/design styles, story plots and reasons of nonsense. Also, I wanted this crossover to be bad.. bad in a good way... so I made really stupid and funny switches to make this really whacky as possible YOU ARE WELCOME xD

*Doofenshmirtz (Phineas and Ferb) as Wreck-It Ralph [Wreck-It Doof] - coz everything he builds gets wrecked in the end... and.. Doofenshmirtz looks like he has bad breath?.. .. I rewatched 'Agent Doof' recently so.. heh maybe I based it from there.. here, Doof staying in OWCA and stuff (.. ehehe.. I'm typing this at 3am, okay?!)
*Ferb (P&F) as Fix-It Felix Jr. [Fix-It Ferb.. HA!] - people have spoken and chose him in majority. Also, coz his name starts with an 'F' and he is also in to building and thus, fixing poop. Felix was by far the hardest to find someone to switch with because this is actually my first crack-crossover-supposetobeendgame-ship in a crossover and I had to pick someone who was both perfect to play as Felix and also vaguely acceptable to ship with Korra. i had help from a lot of people for deciding this (other character choices: Carl, Monty Monogram, Irving)
*Korra (LOK duh) as Sergeant Calhoun [TaKorra Jean Calhoun? .. actually just Korra..] - Because Korra sounds like Tamora... and they're both BAMF ladies... actually I was just curious how Korra would look like in a battle suit XD
*Terra (Teen Titans) as Vanellope Von Schweetz [Taco Von Leche.. I dunno] - they both live in a place they crashed in at some point and they had trouble with controlling abilities and being accepted.. and they were actually princesses (YES! this is the first logical explanation so far)
*Equalists (LOK) as Cybugs [Equabug/ Cyqualist/ Chi-bug/ Chickroach/ Cyquanisha/ Chicyquanishanellanae-nay] - it could've been worse (other character choices: Cabbages, Canyon Crawlers with Bryke's face on 'em)
*Slade (TT) as King Candy [Deathcandy the Terminator.. King] - (SPOILERS!) both him and King Candy died during a triggered volcano eruption haha.. ha :'D
*Lich (Adventure Time) as Turbo [Lichy??.. heh.. 'DOOF'S GON' LICHY?!'] - Lich and Slade have same VA
*Mabel Pines (Gravity Falls) as arcade playing girl [Freakin' Mabel] - based on the episode 'Fight Fighters' coz.. there was arcade things and all.. and her sweater was from that too.. yeah
*OWCA Agents (P&F) as Nicelanders [ehm.. can't think of a name] - akin to Doof's explanation
*Coco, Bloo and Cheese (Foster's Home For Imaginary Friends) as those Q*bert game characters [can't think of a name for this one either] - I chose to have that switch because their show is hardly noticed or appreciated anymore and that's how I see Q*bert in the movie as well (the show's not all bad. plus I happen to like the cartooning style). it was 2am when I thought of it I just wanted to draw them, okay? and Coco was there because Q*bertese equals Cocoese and Carl was one of my choices for Felix and if you Google 'Dr. Coconut'.. ehm.. yeah
*Spongebob Squarepants as Clyde [Soul Eater] - based on the episode 'Scaredy Pants' .. and Spongebob is evil, I just feel it
*Lust (Fullmetal Alchemist: Brotherhood) as Mishaela-ish lady [Me Gusta] - I don't really know
*Slenderman parallel to the Beholder [Slenderbold.. I.. huh?] - the tentacle thingies... (see I told you this was nonsense!)
*Skulker (Danny Phantom) as Kano [Skano?] - they... Robot evil guy type?
*Michael Morningstar/ Darkstar (Ben 10) as zombie [Zuzu?] - well.. he looks like a zombie
*Grim Reaper (The Grim Adventures of Billy and Mandy) as Satine [Grittin?]- I don't know
*Fuzzy Lumpkins (The PowerPuff Girls) as Bowser [Fuzzy Internet Browser] - AGH!
*Senior Senior Junior (Kim Possible) as Zangief [Zenior Zenior Goonior] - I think it was the soft-hearted bad guy persona or something.. I forgot
*Mr. Burns (The Simpsons) as Dr. Ivo [Dr. Ivo Roburnsnik] - because Homer is Sonic and I think this was.. nonsense.. and I liked it.. so there
*Dinkleberg (Fairly Odd Parents) as the Surge Protector - they both get a lot of 'I hate you's (and you know what I'm talking about when it comes to DINKLEBERRG XD)
*Squidward (SS) as Pacman [Pacward.. pfft] - based on the episode 'Just One Bite' because he exploded and was just a head at some point, right? and I thought it'd be fun if he were Pacman and in his game, his goal was to eat all the Krabby Patties.. YES!
*Tahno (LOK) as Markowski [Tahnoski?] - I think Tahno's the type who doesn't like bugs?
*Avatar Aang (ATLA/ LOK) as General Hologram; Avatar Roku, Kyoshi, Kuruk and Yangchen as the other holograms - they were holograms and fade-ishy like what happened to Korra's pre-Avatar state vision of them and.. yeah (other character choices: Cabbage man and cabbages, Lin Bei Fong and metalbending police force)
*Bolin and Iroh (LOK) as other Hero's Duty dudes [Meelo was also suppose to be there too but resolution issues.. eh no that's not their name] - because Korra and they're alive and able to fight off the Cyquanishanellanae-nays.. and everyone else is dead hahahahaha!!! ha :'D (oh glob)
*Robin (TT) as Taffyta Muttonfudge [Taffybird Moby Dick] - originally, I was going for Raven with this, but my sister told me Robin would 'look' better... turns out she's right haha XD (hey, at least I gave him his hair back)
*Speedy (TT) as Rancis Fluggerbutter [Rancid Fluggahbutt] - I don't know
*Starfire (TT) as Candlehead [Starhead] - because.. candles are associated with fire?
*Mako (LOK) as Dr. Brad Scott [Dr. Bra Mascot??] - either I just wanted to draw him proposing to Korra and having a wedding, draw him as an angel, or I'm just plain evil for doing this (hear that? it's my Makorra shipping heart aching....) ... or in other words, let's just say it's Ferb's revenge from their last meeting... ehhh?
*Homer Simpson (The Simpsons) as Sonic [Honic??] - I was craving for donuts and I watched the WIR trailer on Youtube and I thought of donuts when I saw the rings fall from Sonic... then Homer.... I guess I failed this one though
*Major Monogram (P&F) as Mayor Gene [Mayor Monogram.. FINALLY A DECENT NAME!] - he is the boss in the OWCA building, duh..
*The Source (TT) as Sour Bill [The Sour... that's it] - I learned that Tofu candies do exist.. and I like switching the Source with interrogated characters XD
*Hotspot (TT) as Jubileena Bing Bing [Mozilla Google?] - I'm done!
*Cyborg (TT) as Snowanna Rainbeau [Google Chrome] - I AM SO DONE!

Small references

* Krumm (Ahhh!! Real Monsters)
* Kevin Levin/Vicky vandal (Ben 10: Alien Force/ Fairly Odd Parents) - they had episodes that showed graffitis with their names.. I just can't remember the titles.. it's 4am now okay?
* Happy face (Adventure Time) - might make a good transumation circle
* October 3, '11 (Fullmetal Alchemist: Brotherhood)
* Stark Industries (Ironman)
* 'Hunger Games' game (or is it?)
* Police Box (Doctor Who)
* Future Industries (Legend Of Korra)
*Titanstower chibi castle attempt (Teen Titans)

But then again, most of the switches don't make sense so the explanations can be negligible... slightly.. negligible...

Process

I made it with hard work and actual tears from mixed emotions :'D
okay.. All drawn and colored in MS Paint. Linear gradients, nonlinear gradient color bases, and textures are done in MS Paint. non-linear gradients, blur and additional effects are done in RealWorld Cursor Editor. I have been inspired by many artists and Tumblr bloggers lately so my hands slipped XD. My purpose is to be crey and versatile at the same time.
There were like 5 more fandoms and heck of a lot more characters I could have included but because of resolutions and crashing the computer about 5 times, I didn't get to include them. And I finally got to make pixel art again.. yay! (it's hard like always but worth it XD)
WIP:apitongtitan995.deviantart.com…

I'm sorry I ruined/spoiled/killed the movie for you

Other Phineas and Ferb-Teen Titans or Teen Titans-Phineas and Ferb Crossovers

"He Wants To Be A Real Boy"
A Twisted Dress Up*
The End: "Doofsday"
Teen Titans: Wizard of Odd
Apprentice's Aftershock: Busted
Summer Belongs To... Who?
Doof Side Of The Titans Rising
Nevermore: The Gateway To Ferb
'How Long Is The Quantum Boogaloo?' .. Don't Ask
The Quest For The Run Away Runway
The Legend Of Isabella*
Happy... Somewhat... Evil Love Song
General Iroh: Mulan
Bunny Ferb (How to make Slade do the Oppa Gangnam Style)
Wreck-It Doof (you are here)*
*Crossoverceptions

If you want to see the complete list including in progress, extended crossovers, future and pending concepts, click here