You can practice alone in the following modes.

1. Training Ground

By fighting  against dummy characters in the training ground,, you can practice all master characters and guns, including shooting, active skills, and control methods.

2. Training Ground > Kill 'em All

The same with Kill 'em All mode, but you can practice against AI characters.

3. Training Ground > Get 'em All

The same with Get 'em All mode, but you can practice against AI characters.