Mewtwo is a defensive glass cannon. Mewtwo is a bait heavy character that can punish hard with many options.He is gifted with powerful moves , great grounded mobility and one of the strongest projectiles in the game , allowing him to kill in a multitude of ways. Mewtwo can use these to force defensive options and by intimidation , being able to punish bad options fairly well allowing him to excel in the neutral game. His tilts have long ranch making them safer on shield than others would if spaced correctly. However he doesn't come with out his weaknesses. Mewtwo is one of the lightest characters in the game. Combined with his floaty status he can be killed earlier than others. Mewtwo has a slow double jump , making it harder to escape mix up options and some 50/50's. So generally Mewtwo strives on playing as safe as possible and capitalizing on the opponents mistakes.
Mewtwo has a few options that are generally good for him when it comes to his neutral game.
F-tilt : Forward tilt is faster , has increased range and knock back compared to Smash 4. It generally makes a good get off me tool and is decent for spacing. However it does not combo into anything and is has the most end-lag of all of his tilts. It can be tilted up and down to hit at different angles.
D-tilt : Down tilt has increased end lag in Smash Ultimate. (Approximately 3-4 frames) This weakens it's usefulness as a combo starter and makes spacing with it harder and less safe on shield as it was in Smash 4. Despite all this it still makes a good combo starter and has good range. It primarily combos into forward air , neutral air , up tilt , and up air(at higher percentage).
U-tilt : Up tilt is generally good as an anti air and as a potential combo extender. A devastating kill confirm Mewtwo had in Smash 4 was sour spot up tilt into up smash which can work , however it is inconsistent and is not as effective due to the launching mechanics of ultimate
F-air : Forward is one of Mewtwo's best moves as it is great in the neutral , being fast , dealing high damage and shield damage. It is great for spacing if buffered from a short hop and spaced away. However it can only combo at close range. On the plus side , it can be used as a combo starter , extender or finisher as it can combo into it's self at mid percentages and can be combined with down tilt at low to mid percentages. It is also good off stage as it can punish air dodges and is also able to kill very early if used right.
N-air : Although this move has seen some changes(8 hits instead of 9 and smaller hit boxes) it still can do what it did best in smash 4. Keep in mind that this is a very complex aerial(So don't ask me about as I would give a terrible explanation). Neutral air is primarily used to extend some combos as it drags opponents with you. It also great for dragging people of stage. It can also be used as an out of shield option. Do not spam this in the neutral game because it has low priority meaning it will not trade of with a lot of other attacks.
B-air : Back air is a long reaching with good knock back. It is primarily used for keep opponents offstage or edge guarding. It mainly combos into its self from lower to mid percent ranges
U-air : Up air is mainly used as juggling tool but can also be used as a combo extender at mid to higher percents connecting from a down tilt , landing forward air and sometimes double jump neutral air( D.J nair was much more consistent in smash 4 XD). moves that connect with it include neutral air , double jump up air and forward air. It is also a decent kill option at high percents.
Shadow ball : This chargeable special is one of Mewtwo's main tools in the neutral as it can condition opponents to shield or jump.
You can use it to b-reverse and wave bounce to mix up landing options. This move is generally good at dealing damage as it is one of the most powerful projectiles in the game. However due to the nerf on projectiles in general in patch 3.0.0 , it deals much less shield damage.
Confusion: Mewtwo´s side-b is only really useful as a reflector, however due to its high startup it is generally unsafe if trying to reflect a projectile multiple times so it is better to go for a jump after the first reflect. The move counts as a command grab in which you can follow up with an aerial. This also unsafe sense your opponent can act out of the move before you until higher percents.
Teleport : As the name suggests , Mewtwo will teleport becoming momentarily invincible at frames 9-19 and reappear This your main recovery option as it is really your only reliable one besides your double jump. But this allows Mewtwo travel far of stage for edge guarding. Your able to cancel the free fall animation it puts you in by ending the move will sliding off a platform. This is known as a teleport cancel. I will go over more about this when I perfect the technique sense I am still trying to figure it out myself.
Disable : This is meant to be a hard read option for an opponent committing to an unsafe move. It will stun your opponent opening them up for a punish. They will be stunned longer the higher their percentage. Your opponent can mash out of this though.
Some combos to keep in mind : (note dash requires crouch cancel)
Dtilt , Fair , Fair , Fair ? (3rd Fair questionable)
Fair , Dtilt , Fair
Dtilt , Dilt
Landing Uair , Utilt , Uair
Nair , jab> rapid jab
Nair , Dtilt , fair
Utilt , Uair
Dtilt , Utilt , Nair
Dtilt , Nair , Dash attack.(If they miss the tech)
Mid percentages -
Dtilt , Uair
Landing Uair , Uair , Fair
Fair , Fair
Nair , dash , Dtilt , Uair , Fair
Fair , dash , Ftilt ?
Only moves that can really combo are down tilt and up air.
Neutral game and disadvantage state:
Because of how fast passed Smash Ultimate's game play is, it forces Mewtwo to be a little more aggressive than he should be. Despite that , Mewtwo relies on safe pressure forcing options with Shadow ball to condition jumps , down tilt to condition shields or roles , and the same goes for his forward air. Keep in mind when you do get an opening it is important not to over commit to an option because if you space an aerial (or any move) incorrectly you can get punished and this is were Mewtwo struggles because he does not have many options to get out of disadvantage. The nerf on air dodges make this even worse. Combined with his huge hurtbox , low weight , and floaty air mobility makes him kind of a punching bag. Your only reliable escape option is teleport and sometimes forward air. If you can get around these weaknesses then you have yourself a pretty solid character.
Hope you guys enjoy and I hope this is helpful. Let me know what you guys think about my post and feel free to give me feedback.