In Mr Autofire, you shoot and target automatically. You can, however, affect what you shoot by positioning you character. Try staying close to the enemy you want to target!
This is how the targeting system works:
1. The attack targeting is based on proximity of the enemy.
2. Once the enemy is chosen, Mr Autofire keeps attacking this enemy, unless the targeting is reset. When targeting is reset, the closest enemy is chosen.
3. Targeting is reset if a) you take damage, b) you jump, or c) an enemy comes very close to you ("threat range")