"Enemy 2" is the second enemy you encounter. It appears on levels 4, 5, and 6, then comes back to introduce Enemy 3 on levels 8 and 11, and finally takes Enemy 5's place on level 19. It shoots the equivalent of Weapon 1, a 2x2 pixel bullet, straight forward. It has 3 Hit Points.

Phoenix Enemies
EnemyHPLevels
Enemy 121, 2, 3
Enemy 234, 5, 7, 8, 11, 19