Rape 1 is pre-meditated rape with the intent of doing harm, and causing pain.
Rape 2 is spontaneous rape with the intent of doing harm, and causing pain.
And I'm not sure what rape 3 is, although it...
As with any crime, the levels or degrees of rape are defined by state statute. Rape 1 or First Degree Rape has a statutory definition in each state, and may be different in each state.
Rape One is the most serious form of Rape, where the person did the deed with malicious intent; and as such is usually given the stiffest penalties under the law.