Nice game, got me engaged for quite a while
My 2cents would be the movement: I was always trying to not move because at minimum to be out of range of the enemy I would have to spend 1 to rotate, 1 to move and 1 more to turn the turret into the enemy's direction. So I would just wait for the enemy to be in range and while waiting I would be healing. When the enemy was in range the only movement card I would use was the move forward to get in range. I didn't finish the game so I don't know if these cards might have been useful on later levels.
Besides from that it really got me hooked, I like these kind of games where you need to strategize to win :)