I liked the concept behind this one to have to keep fixing your submarine more and more frantically to keep going deeper. As another comment mentioned, either a bit more of a delay on the intro dialogue or maybe a speech bubble with a click would be a great improvement. I'm a very fast reader and I lost a few of the later, longer text lines because they faded too quickly. With the levels where one of the screws is missing - is the only goal for that level to place the screw and tighten THAT one, or still tighten ALL of the screws in the level? Either way, nice concept!