It would had been best, if the towers did produce some kind of bullets by themselves but 1) I had this Idea too late and 2) I'm not that good to implement soo many then needed sprites at the same time. So animating the enemy, when it is hit, was a compromise.
When one enemy is hit at field x for example this field is not able to attack another enemy for some frames. So mostly, the first enemy is attacked and only later in the game, when in one phase more enemys are spawn, the last-ones will be attacked by the same field x again (as you can see by the "fire"-animation).
Yes, the range of the turrets is 1, so that one turret, surrounded by 8 fields, attacks enemys on all these 8. Air-Enemys will be attacked by the field in front of the tower, when they are above the tower and by the field behind the tower.
Especially in the first levels, the slow-towers don't make very much sense. And indeed I don't use them very much.
