How does Online Mode work?
Online mode uses something called Adobe's RTMFP. Basically, to put it simply, Flash connects you to our servers when you log in, then connects you directly to your opponent the best way possible if possible. SSF2 has a backup plan if this fails, but it might be a little slower in practice. You will want 'P2PMode', meaning a direct connection, any time possible.

Why aren't you using "Rollback" technology?
Rollback just does not work very well in a fighting game, let alone one with as much movement control as SSF2. With recovering, edge tactics and the like requiring a strict, reliable, and accurate perception of your location and your opponent...there just isn't room for characters garbling around the screen as rollback attempts to make sense of the input delay on your end and update your foe's position. Imagine going for a meteor smash and then suddenly your foe appears on-stage!

Thus, as the official Smash titles have done, we're using traditional netcode offset by a slight input lag. But, our backend is much more optimized than Brawl's. This should mean no more than a few frames of input delay for a good connection.

When I log in, nothing happens!
This means that RTMFP doesn't work with your network's settings. This is probably going to be super annoying, but if this network is yours, you have to do some tweaking to get it working. The easiest (and most reckless) way to do this is to set your computer as the network's DMZ, or DeMilitarized Zone. This breaks down all of your network's defenses for your computer, leaving it wide open for information flow. This can be unsafe, however, if someone is attacking your network. Otherwise, you might have some Googling and Port Forwarding to do.

How can I speed my gameplay up?
1. Plug your computer directly into the internet instead of using WiFi.
I know this sounds crazy, but in this day and age, WiFi is not perfect. P2P connections rely on speedy sending and speedy receiving and has little room for error. If you press A and your WiFi signal loses that button press from interference or some other cause, the game will stall. You are sending 30 of these per second, and you can't afford to lose any. Let's take wireless out of the picture to leave less room for error, if possible.

2. Make sure this person isn't TOO far away.
This is a given, but some people don't know this - the internet isn't all that efficient. It's a bunch of tangled webs and it sometimes doesn't know which way is fastest. The farther your opponent is, the more twists and turns that the internet has to figure out. It may not be possible to play someone from extremely far away if you don't get a good connection to them, unfortunately, so choose your friends wisely.

3. Upgrade your internet/complain to your internet provider about possible high latency/packet loss.
If all else fails, it may be time to think about contacting your internet service provider (or ISP). Certain types of connections have higher latency than others; SSF2 online will never run well on Satellite internet, mobile connections (4G, 3G, etc.), or Dial-Up. However, if you don't have any of those types of connections and you still have high latency (AKA ping), calling your ISP and setting up an appointment with a technician is important. It could mean that your hardware is installed incorrectly, or may need to be updated.

4. Make sure both computers are fast enough to run SSF2.
Naturally, if SSF2 is slowing down on either of the computers, it will slow both down. Make sure your opponent and you are both running SSF2 at a solid speed.

I can't play any matches with anyone using low latency mode, and high latency mode is too slow/doesn't work!
Unfortunately, Online Mode is limited in this initial release. You may have to wait until a later patch to enjoy it using high latency mode - you have a special kind of connection that will need to rely on a that mode, which is not 100% working in this release. You may be able to get better speeds if you play with other people that have this special kind of connection, as that will allow you to use low latency mode - but they are extremely rare. In the future, we will be able to speed up the solution we're using, but for now you are, unfortunately, out of luck.

More to come!