Not a great deal of analysis is needed to track the effects of Mephistophilis on Faustus. The changing effects are rather clearly demonstrated in the text. [Note: Marlowe's Doctor Faustus spells the demon's name as Mephistophilis while Goethe's Faust spells the name Mephistopheles.]
In the beginning, Mephistophilis effects Faustus with no more than amusement. He is happily surprised that he can order a demon of Lucifer around so easily. Faustus feels superior to Mephisto and condescending toward him.
FAUSTUS. I charge thee to return, and change thy shape;
How pliant is this Mephistophilis,
After Mephisto begins to impart information to Faustus, Mepisto effects him with a sense of appreciation. This appreciation is not longlived though. Soon Faustus is effected by scorn and hatred. The book of the cosmos given Faustus by Mepisto makes Faustus regret and long to be reinstated among God's followers.
FAUSTUS. When I behold the heavens, then I repent,
And curse thee, wicked Mephistophilis,
When Faustus receives rebukes and Mephisto brings Lucifer, then Faustus is effected by fear. Lucifer enters with Mephisto and subjects Faustus to an entertainment by the Seven Deadly Sins with the intend of bringing Faustus into submission; the attempt is successful.
As the Chorus explains, Mephisto's effect on Faustus is to entertain him. They visit many places including the Pope's court where Mephisto makes Faustus invisible so he can play tricks:
FAUSTUS. Then charm me, that I
May be invisible, to do what I please,
Unseen of any whilst I stay in Rome.
The ultimate effect Mephisto has on Faustus is to terrorized him. Since Faustus begins to respond to the Old Man's encouragement that Faustus seek forgiveness and repent, Mephisto promises that not only will Faustus's soul suffer in hell but that his body will be dragged down and suffer torment there too. Moreover, Mephisto will torment Faustus with unspeakable pain while he is still alive. Ultimately, Mephisto effects Faustus by sending his demons to drag Faustus to his punishment.
CHORUS. Cut is the branch that might have grown full straight,
And burned is Apollo's laurel-bough,
That sometime grew within this learned man.
Faustus is gone: regard his hellish fall,