I've been playing Mewtwo all day. I want to share with you guys some good things I saw playing as him.
1) Dtilt: Dtilt is an amazing zoning move and combo initiator.
-Dtilt sourspot can be followed by Fair or Utilt (low %s) and Uair (mid %s). This works pretty well against fast falling characters like Fox, Falco, Captain Falcon, Sheik, ZSS, etc.
-Dtilt can stop Sonic's full charged Spin Dash and poke Luma away (if Luma is like over 10%).
-Dtilt's sweetspot sends the opponent away (helps to get some room to charge Shadow Ball).
2) Utilt:
-The sourspot sets the opponent above you (nice for followups).
-The sweetspot (if the enemy is grounded) sends the opponent infront of you downwards. At low %s, if you fire a fully charged shadowball you can hit their tech.
-Sometimes Utilt's sourspot put the enemies over your head, if you buffer an USmash you'll get a true combo of 20%. This works over 100% so it probably will kill the opponent.
3) Confusion:
-Interrupts momentum. That's incredible usefull. Sometimes after your second jump you find yourself trying to land but your opponent is guarding your landing spot... Side B away safely.
-Helps Mewtwo's recovery stopping momentum while moving forward and screws the enemy's edgeguard timing.
-If the enemy don't respond quickly, you can hit him/her with Utilt or Uair after Confusion.
4) Disable:
-I find it A LOT easier to land than melee.
-You can catch your opponent off guard doing stuff like SH+Fair without hitting, then DownB.
-Jab to DownB works very consistently.
5) NAir: Amazing.
-Virtually no landing lag. You can chase your opponent and grab him/her after you land with them during NAir. You can do cool stuff like NAir > Jab > Disable if your opponet lands infront of you or if you turnaround quickly and jab.
-Good to prevent punishes.
-Good for edgeguarding and stage spikes.
6) DAir:
-I tried to spike my opponent off stage. Killed him off the top lol. Its a kill move at high %s.
7) BAir:
-Your main tool for edguarding. Keeps the enemy at bay and is a kill move at high %s.
It's an excellent character. Hits like a truck. Lots of killing moves. Nice combo and string options. A lot of movility and recovery. I wouldn't be surprised if someone becomes a monster playing as Mewtwo.