Character Analysis
If you got to know the character of Snape from this movie alone, you'd be hard-pressed to find a single likable thing about him. He's a full-on Death Eater without a shred of sympathy for anyone not loyal to Voldemort.
At least, that's what he appears to be.
Exhibit A of Snape-as-villain: he spills the details of exactly when Harry Potter will be moved from his aunt and uncle's house:
VOLDEMORT: Severus. I was beginning to worry you had lost your way. Come, we've saved you a seat. You bring news, I trust?
SNAPE: It will happen Saturday next at nightfall.
It's looking less and less likely that Snape is still playing at being a double agent. As far as this film is concerned, he's dead set on getting Harry killed.