- Sonic needs to be unlocked
Sonic, fittingly, has the fastest running speed in the game. His special moves and aerial v+A also cause his trajectory to abruptly change. Unfortunately, his actual attacks are short ranged and weak in comparison to most characters. Sonic players must therefore rely on his extreme mobility to keep the opponent confused (or to gain items, if those are enabled.) Sonic is fast on the ground but suffers from a low horizontal speed while in the air.
At competitive tournaments, where items are generally disabled, Sonic suffers from a lack of kill moves which are both safe and effective. He usually has to anticipate a mistake from his opponent to hit with a smash or back aerial, or a high altitude up aerial kill.
Dash attack, >+B, and v+B are all variants of Sonic's iconic spindash attack. His ^+B gives great vertical distance for recovery and the spring that falls can do minor damage to enemies below, potentially spiking them.
When facing a Subspace Emissary Mode boss, try this: jump, >+a (optional), ^+B, v+a. this a pretty nice for racking up some damage.
Pummels and Throws
Super Sonic: Sonic summons the seven Chaos Emeralds and turns into Super Sonic making him able to fly over the stage. When you are transformed into Super Sonic, you can tackle your enemies and blow them away with a high velocity strike. This move works best if the opponents are on a flat area so that you can hit them repeatedly without worrying about them getting away. If you are having trouble with people that endlessly air-dodge, just hover next to them and wait until the dodge ends, then charge them. This is one of the longest Final Smashes, clocking in at eighteen seconds.
Falco is similar to Fox and Wolf, but any good Falco player is skilled at using his differences. Falco's laser is stronger and slower than Fox's, but not as much as Wolf's. If he is using it on you just use the Side Spin move. The hop at the beginning will stop any lasers that hit you, allowing you to reach him easier. However, due to his Reflector you will have a hard time reaching him. To counter this you will have to employ a strange feature of the Side Spin move. What you do is begin charging it up, but about halfway through the charge hit the standard attack button and let go of every button (including the control stick). If you did it right, Sonic will do a really fast leap forward that will send him about the distance of a long Homing Attack. This will allow you to approach him without being subject to Falco's Reflector and lasers. From there, knock him off the side of the stage since Falco falls fast and has bad vertical recovery. If you have Falco off-stage, jump after him and hit him with an aerial attack (avoid using +) and then Spring Board back to the ledge. However, beware of chain grabs! Falco's chain grab can easily rack damage up on you if you can't escape it.
If you're against a good fox user don't use your rolling charge against him, he'll just A+> and potentially get a free kill. Try to stay close to him as you should be able to combo him continuously with faster moves. If he gets away, wait for him to come to you unless he starts using his blaster. In that case, try to just run at him and hope you can time a dodge past him when he begins to do one of his kicks. If you're good with your dodges this fight should be easy, if not you'll more than likely lose.
Kirby on the other hand is a harder one. He can suck you up and spit you out if you dare to use spin dash on Kirby. Regardless, use your final smash if you have the chance. His stone and hammer attacks are powerful. If he uses his rock attack, try to dodge and use the opportunity to dash in for a grab.
As Sonic, you're going to have a pretty hard time going up against Lucario because of his superior hit range and fast attack speed. Similar to many other characters, you're going to have to wait and watch for your opponent to make a mistake, and pummel them before they have a chance to stop your movement. Because of his large hit range, Lucario can stop your dash attacks and punches pretty easily, so you're going to have to play it safe with hit and runs. Your best bet for victory is going to be catching Lucario off guard with spin dashes (both smash and special) and mid-air kicking. Reccomended: Do not try beating Lucario in a fist fight; His punch range will take you down every time. rely on Sonic's speed and take few risks.
Considering Luigi's all-around skills in fighting, this fight can be a tricky one to win. If you are accustomed to using Sonic, then it will be easy. Luigi has those occasional hits that send you flying (similar to Zelda, only much less often). Be wary of his jumps, as they can be deadly if they hit just right. He has good ground and good aerial attacks, but not amazing speed. Use this to your advantage. Finally, beware his final smash. Right before he does it, double jump and use your special move to get out of the way. Then run away from the area he has infected.
This will be quite a difficult fight, as Mario has many tricks up his sleeve. If you knock him out, he can do his b+forward and just get back in. His aerial attack will give him a huge advantage, as Sonic is not very good at aerial. Just keep trying to attack him with fast moves. Don't stay too close to him; stay at a mid range and wait for him to come to you. If hes using an aerial attack, use up+b and then down+a. That will most likely hit him and deliver good comeback, but beware if this misses Sonic will be very vulnerable.
Essentially, Lucas and Ness can be considered the same enemy when it comes to strategies.
Lucas is very similar to Ness, except for a few attacks. The main difference, and one that you need to know about, is that Lucas's attack causes enemies that are hit by it to freeze in place instead of damaging them like Ness. Though the effect is different, Lucas' freeze can give him the opportunity to smash you out of the stage, so it is best to avoid being hit by the freeze at all costs. Freeze can move further, it moves faster, and it has a bigger radius of effect than Ness' , so it will be harder to dodge. If your percent is high, it will send you flying vertically instead of just freezing you.
Also, Lucas's side attack (PK Fire) pushes the opponent instead of Ness' which traps them and burns them for a little while. This is great for edge guarding against Sonic, so beware that he may use it against you.
Lucas' absorb (+) attack only work from the way he is standing. This only gives you an advantage when throwing items at him, as ricocheted projectiles may have a better chance of hitting him in the back. This is a minor point and not applicable in no-item fights, so don't worry about this absorb.
Since Meta Knight doesn't have any long range attacks and his close range attacks are devastating, use hit-and-run tactics. If possible, do this: Go to one end of the stage and use Down-B. Hold it there until Meta Knight is just about on the ground, and release. This works best on Sonic's stage. If you acquire any long range items, use them as much as you can. Ray Guns and Star Wands, probably.
Ness would be a difficult enemy to fight with Sonic. His wide selection of long range attacks, like PK FIRE (B+Side), or PK THUNDER (B+Up), provide positive effects to Ness's behavior in battle. These attacks would work very well on Sonic, because he is always moving, but not with people from the STARFOX saga, because of their reflection attack. A good attack to use against Ness with Sonic is his B+Down attack, because it provides unbeatable speed and traction that B+Side can not provide. Beware Ness's B attack, PK Flash which he can control. It is easy enough to dodge, but if it connects, it will provide power greater than Samus's Charge beam. The best way to dodge it is the side-step move, or you just run.
Pit is a good match up for Sonic. Sonic is one of the most aggressive characters in the game, with an array of fast attacks, while Pit is by far the most defensive, with two reflectors, spamming projectiles, a regular A Spam and incredible aerial mobility. Pit's defensive nature can cut off most of Sonic fast attacks and can make approaching a difficult task, even for Sonic.
Snake is one of the most powerful characters. His basic and special attacks have very dreaded results which is a high KO rating and his grenades can be thrown back to him if you pick it up carefully and quickly.
Sonic against Sonic? That is insane and difficult much due to both Sonics will run pretty fast and attack pretty fast. The one thing to be aware about is the final smash which makes your enemy invincible and faster and will take you out within seconds.
For starters Wolf is pretty fast, but not as fast as you if you are playing as Sonic. Wolf's delay after he is dashing is much like Sonic's; they have a lot in common. Just dodge his lasers and remember that he is strong and fast too. Sidestep his lasers and run up to him then grip – if you can grip him at the very edge, throw him off then use dair (in air down attack, jumpX2+up super smash+down air attack) on him while he is trying to get back to the stage.