Landing Lag
The elephant in the room. I will be blunt. Some moves have been given more landing lag. Sonic's bair. Falcon's knee. Air dodging.
However...
Many (I'd actually say the strong majority of) moves in the game have basically little to no landing lag. It was very easy to identify them quickly simply through playing. I believe that this whole landing lag thing is suffering from a near-sighted syndrome effect. People are playing the characters they like in the way they always have, and when they come across a move they are used to using a lot and it seems to have a bit of landing lag, they suddenly attribute that to the entire game. Now all of the sudeen every single aerial has more landing lag?
The fact of the matter is that landing lag isn't so serious as has been blown up to be.. It does make characters affected feel [/i]different[/i] to play, because you need to change how you move and what abilities you use. You have to adapt, but it certainly does not make the game slower.
Overall, I can say with confidence that the game is not suffering from some kind of overall landing lag issue.
Combos
Tilts.
Tilts, tilts, tilts.
Tilts are going to be huge. Most experienced players know how important good tilts are for combos and that seems to be the case here. In any case, combos tend to become way more difficult when your opponent is at higher %s, but at low %s combos are definitely a thing. Something about the way the characters connect in this game has been seriously changed from past iterations.
Advanced Techs
Brawl dash dancing. No wavedashing. No l-cancelling but there is teching (or maybe it was auto-cancel? Hard to say...) Pivot cancel is still in. You are able to do tilts as well in the same way. It's pretty neat. I wouldn't say it's like the definition of a meta, but it's a neat trick for mix-ups.
Ledge Mechanics
Okay, lets get this explained.
The ledge snap has been nerfed significantly. It's way more similar to Melee than Brawl. I don't know frame data for Melee so I wont' say it's the same, but tbh I think it may just be a tad more forgiving than Melee, but it is definitely nerfed.
There is a small "ledge immunity" after letting go of a ledge. The ledge immunity is to you. I tested this extensively with Ike, Megaman, and Charizard.
Basically if you drop off the ledge (in a manner that you would do if you were trying to maybe stall there), the ledge actually becomes un-grabbable (is that a word? lol) for a very small window of time.
For example if you are Charizard and you drop off the ledge or get trumped, and you hop very quickly back to the ledge, you will not grab it. You will just fall right past it.
Characters with flips for their 2nd jumps or anything resembling a buoyant animation (like Kirby) are less affected by this and I'll tell you why. It seems that the game waits for some of the ending frames of the characters flip animation before enacting the grab mechanic. I tried with Marth and Shulk who both have flips, and they basically just bumper car'd the ledge until their flip animation was done, then they would grab it. Characters like Charizard, Megaman, and Ike would just not grab it at all and fall. The details around these mechanics needs to explored a lot more, but overall, I think the off-stage game has been given a whole new make-over.
Game Speed
The speed of the game is...omg this must be so surprising to hear, but it's inbetween Brawl and Melee. However...air speed is still closer to Brawl. Ground speed is very Melee feely though.
Fast falling is incredibly fast though.
Shields are fast. Very fast. They are basically the new wave-dash (I dare say), I'm being totally serious, and you can attack out of them with a great deal of attacks.
Overall
This game did not feel like Brawl, and I've been playing a lot of Brawl lately to prepare and I almost feel bad for doing so. It actually felt more like Project M, to be honest if I had to compare it to something, but when it comes down to it I almost feel like I'm insulting the word put in to this game to simply size it up to some previous iteration.
This game has soo much freakin' stuff in it. I now understand what Sakurai was saying when he said they basically rebuilt all the characters. Even though many characters possess the same movesets, you can really tell they aren't the same. The animations have been rebuilt from scratch. Peach has mostly the same moveset, but her body moves so intricately and 100% differently in the way that she executes them. It is absolute madness to witness.
I really do believe the characters were built from the ground up. Same move-sets withstanding. Characters interact with one another in a way we've yet to see, the hit-stun in Smash 4 is unique, and the characters have had literally everything touched up.
Blah, blah, excited to play the game, blah, blah. Let's get this AMA going.