Street Fighter IV Cheats for PC

The following colours can be unlocked by beating the indicated challenge on either Time Attack or Survival mode.
Unlock Color #3:
Beat Time Attack #1
Unlock Color #4:
Beat Survival mode #1
Unlock Color #5:
Beat Time Attack mode #6
Unlock Color #6:
Beat Survival mode #6
Unlock Color #7:
Beat Time Attack mode #11
Unlock Color #8:
Beat Survival mode #11
Unlock Color #9:
Beat Time Attack mode #16
Unlock Color #10:
Beat Survival mode #16

When you have beaten Arcade mode once the character that you used Prologue and Ending movies will become available options at the Gallery menu.

When you complete Arcade mode with the two characters that are in each special video you will be able to view it in Gallery mode.
Unlock Ryu Vs. Ken Video:
Beat Arcade mode with Ryu and Ken.
Unlock Guile Vs. Abel Video:
Beat Arcade mode with Guile and Abel.
Unlock Chun Li Vs. Crimson Viper Video:
Beat Arcade mode with Chun Li And Crimson Viper.
Unlock Gouken Vs Akuma Video:
Beat Arcade mode with Gouken and Akuma.
Unlock Seth VS. M.Bison Video:
Beat the game with M.Bison and Seth.

Complete character-specific trials in Challenge mode in both Normal and Hard mode and new gallery artwork of the character you used will become available. Each trial you do will give you one new piece of artwork.

It took a while of research, but I've found the real way of unlocking Akuma after unlocking Sakura w/ Ryu, Dan w/ Sakura, Fei Long w/ Abel, Gen w/ Chun Li, Rose w/ M. Bison, and Cammy w/ C. Viper:
1. Set your Arcade settings to 1 round, 99sec, and minimum Difficulty LV of Easy. Also, might be a good idea to turn requests off so that others won't disterb the process.
2. All you need to do is get 1 Perfect and not use any continues. That's it. After you beat Seth, a slash should appear over the screen signaling Akuma's appearance. If nothing happened after Seth, then you must not have met the standards.
3. Beat him quickly. He is a heck of alot of trouble to fight, but, lucky, his defenses doesn't match his strength. Zangief will have a party with him.
4. After he concedes defeat, he becomes playable.
Now that Akuma is in, train with him for a bit. You'll need him to help unlock Gouken, Ryu and Ken's old master.
1. Beat the game as Akuma. You can set it Easiest if your having trouble.
2. Set the Arcade settings the same as before with Akuma. Requests, must definitely off. You'll need to focus for this one.
3. Choose someone you know well. Now here are your stipulations:
1 Perfect
3 Ultra Combo Finishes(not Super)
5 First Hits
And No Continues
Yeah, alot of work, but trust me it works. When your finish with the stipulations, your free to fight how you want. You should keep a count of what you've done, so you won't get confused.
4. Same with Akuma. After Seth, a slash should appear over the screen. Your fighting at the same place as Akuma, but this time it's Gouken, stronger in both offense and defense, master of the RyuKen style. He will Not be as easy as Akuma to take down, but I still recommend Zangief to end the battle quickly. Master how to get to get in close to the opponent and get his throws out quickly.
5. He becomes playable afterwards.
Now that he's in, train. For he's the key to unlocking Seth if you've already Beaten The Game With Every Other Character.
1. Set the Arcade setting to Easiest, 1 round and 99sec, to get it done quickly. When your done, Seth will be unlocked.
Note: Seth, in reality, is weak in both offense and defense. To not take much damage, you Must train to learn when to pull off moves that will save you from being KOed quickly.
OK I'm done. Hope I helped, JCP Da Blitz.

Complete the following tasks in Arcade mode on any difficulty setting to unlock the corresponding character (If you want to unlock the characters easier set the difficulty to the easiest setting with one round).
Unlock Gen:
Complete Arcade mode with Chun-Li.
Unlock Rose:
Complete Arcade mode with M. Bison.
Unlock Cammy:
Complete Arcade mode with Crimson Viper.
Unlock Sakura:
Complete Arcade mode with Ryu.
Unlock Dan:
Complete Arcade mode with Sakura.
Unlock Fei Long:
Complete Arcade mode with Abel.
Unlock Seth:
Complete Arcade mode with ALL the other characters (including the bonus characters).
Unlock Akuma (Gouki):
When you have unlocked ALL the characters (except Gouken, Seth and Akuma) play Arcade mode with any character and get at least 2 'Perfects' and 2 'Ultra Finishes' to fight Seth. When Seth has been defeated you will then battle Akuma who becomes unlocked when you defeat him.
Unlock Gouken:
When you have unlocked Akuma, play Arcade mode with any character and get at least 2 'Perfects' and 3 'Ultra Finishes' to fight Gouken after defeating Seth. Gouken then becomes unlocked when you defeat him.