Sonic the Hedgehog was here.
Ah! Beat me to it! XD
He is too fast , is it ok ?
No. "too" would be «demais» or «demasiadamente»: «Ele é rápido demais.» or «Ele é demasiadamente rápido.».
He is really fast? Is that an incorrect translation?
That should be accepted!
Technically, it is incorrect. "really" is akin to "truly," which would be «verdadeiramente», and "very" is «muito», but the two words in English are used very interchangeably in everyday speech. ;D