OK, here's A LONG and detailed thingfor you to read about the gameplay:

Basic Stuff
Even this is BASIC stuff that nearly every SF has, it’s good to remember what’s in:
-   Walk: Back and Forward. Oh yeah!
-   Side Change: that’s when the rival jumps over you, changing your position from P1 to P2 and vice-versa.
-   Crouch:
-   Jump: Back, Neutral and Forward.
-   Dash: Back and forward.

Added Basic Stuff
This is what SF could benefit from. We saw things like these in other SFs, CvS or SFxT. Even in MvC!!
-   Dodge: this is for avoiding a rival’s attack(somehow). However, SF NEVER had this. Otherwise, we can use these animations for something original to our project: the Overdrive Attack (explanation in SFG speciffic stuff)
-   SFxT dodge: Is what Tekken’s characters performs for avoiding a projectile attack. I suggest merging this one with the previous.
-   Chain Combo: It comes from Darkstalkers. It’s just chaining some attacks, starting the combo from weak to hard.
-   Air Blocking: It comes from XvSF. This could be VERY useful against “jumping whores” as Claw.
-    Throw Recovery: SF2 had this, even it was a bit…”sloppy”, for saying it in a word. You were thrown in the air and you just “recovered” with a 2-3 sprites animation. Let’s do this more dinamic, as in this animation:
<< Thanks goes to BALTHAZAR.
Do you remember that awesome SF2 movie? Speciffically, do you remember the Ryu/Ken combat against Dictator? That’s what Dict’s performs when he’s thrown by Ken(or Ryu? Gotta rewatch that awesome fight!)
-   Zero Counter: It’s what gives its name to the Zero/Alpha saga. A rival is attacking you and while you’re blocking, you can reverse the attack. We can make a better thing for this, as converting some zero counters into speciffic stuff, such as throws(as in Tekken), or powerful attacks(as in DoA). This can make the combat something more spectacular. This is going to be the Reversal system, at SFG Speciffic STuff
-   Drammatic Battle: or in today’s slang: Tag teaming! Again, SF2 Movie for references, Ryu and Ken giving EVERYTHING against Dictator.
-   Super Combo: This is what SSF2: GMC put as its mark(aside new attacks for nearly everyone): this is the VERY first SF game where a powerbar appears. A powerbar that allows you to perform a super combo, more destructive than a normal one, and with some flashy and awesome shadows around the character. This later was developed as the A/Z-ISM in  SFZ3.
-   X-ISM: This is the classic SF system.
-   V-ISM: It’s based on the custom combos. What is a custom combo? It’s SFZ2 mark. Basically, the chain combos from Darkstalkers, but a bit more spectacular.
-   A/Z-ISM: The Super Combo system previously explained.
-   Guard Bar: Basically a bar which when’s full allows us to protect every attack. But when we’re short of, we’re open to be attacked D:!!
-   Guard Tech/ Throw Guard: this is the same thing, but from SFZ and SF3. In SFZ we just avoid the throw, reducing the “pain” we suffer, while in SF3 we receive no harm from it)
-   Blocking: This is SF3’s saga mark. It’s a defensive method which aside protecting you, gives us the opportunity of attacking the rival before he/she recovers, to move first. It could be performed in the crouch position, and standing has two variations: against normal(standing) attacks or against aerial attacks.
-   Stun Gage: another “power” bar. This one shows us when we’re going to be dizzy(stars, birdies, etc). Some characters had a longer bar than others in SF3.
-   Leap Attack: it’s a mid attack that avoids lower attacks(it’s a short-jump attack):

-   Personal Action/ Taunt: SFZ’S and SF4’s had no utility, aside the fun spot. In SF3, this is different, since it’s also possible hitting the rival.
-   Ultra: Coming from the SF4 saga. Spectacular attacks, gotta say!
-   Focus: SF4’s mark. It’s an attack that inks our character and also the rival.  We can avoid the ink thing.

SFG speciffic stuff
And…this is the point where we HAVE to be creative. These are the things I suggest:

-   Overdrive Attack: It’s an attack coming from a dodge animation. SF2 movie’s Ryu vs Fei Long as reference. Ryu’s on the floor, then dodges, and kicks Fei’s face, allowing him to chain a longer combo(in the movie it's a Tatsumaki)! This is the use it could have, creating a combo from a certain distance, just using the dodge as a link. These could give a “!!!” factor, forcing players to play near the rival, since from further distances…there are only projectile spammers(hello, Ken!) and Overdrivers!!
-   Throw Recovery: Wait, I already told this! Well, ours could be more dinamic. SF4 Juri’s movie has some awesome examples. Cammy throws her from her “hooligan combination”, Juri recovers in the air and then jumps  FROM THE WALL, starting a combo!! This throw recovery could have different properties, depending on the character: jump to the wall, “teleporting”, going to the floor, compatible with a CHARGE(example: you’re playing with Claw, and you’re thrown, then before hitting the ground apply the recovery, and the Rolling Attack could performed from here, making him a bit more dinamic)
-   Reversal: This is something better(at some point) than the blocking system, because it directly attacks the rival while you’re ABOUT to be harmed. That’s to say, avoiding rival’s attack with one of your own. As the throw recovery, it could have different properties for different characters: some could perform a throw, others a powerful attack, etc.
-   Guard Breaker: Let’s break turtle’s armours!! Do you hate when a rival blocks EVERY damn attack? Let’s break their walls and start a combo(e.g: a chain combo!)!!
-   Combo Breaker: OK, OK, I was a Killer Instinct player back in my…14? I still remember that feeling of: what if I make a long combo? Will I be combo breaked? If so, will it be a LONG reverse break? . Of course, just change that name!!


And this is basically the system I have in mind. Some things could be merged(as Zero Counters with Reversal, etc) with others, while others could be erased.

The question…MAYBE some of this stuff is executed the same way(example: Leap Attacks and Focus are both pressing MP-MK). We can make two things:
-   Develop an –ISM system: This could convert our project in something awesome, making possible like…as many ways of playing with a character as many ISM involved in game! Of course, the negative point is the extra-difficult while coding.
-   Just change the execution of those which can give problems. If Leap Attack is MP-MK, then Focus could be HP-HK. The negative point is that it could get a bit confusing for starting with the system: imagine you want to leap attack and you perform a focus attack that leaves you totally opened to a combo from the rival D:!!!

- Ryu/ Ken fight against Dictator(SF2 movie):
http://www.youtube.com/watch?v=I056MPrakoQ

- Ryu vs Fei Long fight(SF2 movie):
http://www.youtube.com/watch?v=yTeFELGlbdA

- Cammy vs Juri fight(movie):
http://www.youtube.com/watch?v=WzGnPgWpRNk