Nice art & concept, my main complaint would be the time thing as others have mentioned.
In fact, I think it would be interesting if you got rid of the time thing entirely and instead made the countdown the number of actions per turn.
For example, say you had 6 actions. Each square you move counts as one action, and each attack could count as one (maybe some could count as more). The enemies would also follow the same system.
While allowing you to attack at any point in the sequence, this would create an interesting positioning game where you can use your actions to approach and retreat, but each attack would detract from your ability to move around, forcing you to plan ahead.