Super Street Fighter IV/Universal Abilities/Ultra Combos
Probably the most stand out new feature of the Street Fighter IV series is the Ultra Combo. Ultra Combos are similar to Super Combos in that they require similar motions to active, but they also always require a simultaneous press of three Punches or three Kicks to activate. They also do Chip Damage as well. They are generally more powerful than Super Combos at their highest damage and are a lot more flashy than Super Combos. In most cases, Ultra Combos, when they connect, are very cinematic: they go into canned animations with dramatic camera angles and fancy-looking attacks.
And that's actually one of the biggest differences between Super Combos and Ultra Combos: a large number of Ultra Combos have to connect a specific "trigger" hit to actually connect fully. If these trigger hits are blocked or if they whiff, then the Ultra actually goes into a secondary, alternate behavior. Examples of this are Dudley's Corkscrew Cross, where if the first hit connects, he'll go into a long, drawn-out animation punching the opponent into the wall. If it whiffs, it will just perform the Corkscrew Blow from Third Strike. Cammy's Gyro Drive Smasher and Fei Long's Rekkashingeki both have trigger hits that, if they do not connect, the Ultra Combos just go into a behavior nearly identical to their Super Combos. If they connect, they then go into the cinematic combo.
Select Your Ultra
Every character has two Ultra Combos to choose from at the start of a match. The Ultra Combos usually serve different purposes to cover different holes in their games and to help against specific match ups. For example, T. Hawk has a standard grab Ultra in his Ultra Combo I, but he has an anti-air Ultra Combo to catch people trying to Jump away from grabs in Ultra Combo II. For Rufus, Ultra Combo I is great for Combos against characters he can rush down, but Ultra Combo II is better against projectiles like Hadokens for characters that can keep him out with those projectiles.
The Ultra Meter
The most distinctive thing about Ultra Combos is their requirement for use: unlike EX Moves and Super Combos, Ultra Combos do not need any Super Meter. They have their own Ultra Meter that actually builds up when you take damage! Because of this, it is 100% guaranteed that you have an Ultra Combo at some point in the round before you actually are defeated. Also, you do not keep Ultra Meter between rounds if you do not perform your Ultra Combo. And, as mentioned before, Ultra Combos generally do a large amount of damage, especially if your Ultra Meter is full.
These three factors are what make Ultra Combos the ultimate comeback tool. There's no reason to "save" Ultra Meter for the next round and you will always get one before you die. And they do a ton of damage so they are there specifically to provide players a means to generate a comeback.
It is worth noting that Ultra Combos also come with the distinction of not being able to be canceled into from anything else. You can never cancel a Normal Move nor a Special Move nor an EX Special Move into an Ultra Combo. Even the Whiff Cancelable Normal Moves cannot be canceled into Ultra Combos.
Here to Stay
Love them or hate them, Ultra Combos are one of the main features in Super Street Fighter IV. So you better get used to them.