Use the following to switch between characters in the middle of the game. For example, if you choose Cable, Ken, then Ryu, but later in the second stage you want Ken to appear first, hold L for the second character and R for the third character at the versus screen.
Same character selection
Unlock everything in the shop and get a 99 experience level to select the same character up to three times in arcade mode.
Alternate costumes
At the character selection screen, highlight a fighter, then press A or Y.
Cheaper hidden characters
Exit and enter the shop screen until the price of the hidden characters are lower.
Get points without playing
You can get ten points a minute if you go to training mode, choose your characters and opponent, then leave the game on for about five hours. Note: Do not pause the game. Additionally, a good time to leave the game running is right before you go to bed.
Defeating Abyss
Select Cable. For Abyss' first form, just block his attacks and then press Y to shoot. Repeat this until he dies. For his second form, distance yourself as far as possible and press Y to shoot. Repeat until he dies. For his third form, just use Cable's Hyper Viper. It takes off 90-95% of his life in one blast and will be a 115-130 hit combo. Then, just hit him once or twice with any attack to defeat him
115-hit Team Hyper Combo
In any mode, select BB Hood, Cyclops (or Ironman) and Cable. When you get charged up to level 3, select BB Hood and make sure she's about 1-horizontal body length away, then initiate the Team Hyper Combo. If done correctly, it should result in a 115-hit, 85-90% life drain to your opponent !