Bermuda Triangle Tutorial Help, Please

I was following the Bermuda Triangle tutorial, which is pretty comprehensive, I think. I've been enjoying it immensely and can already see how to implement a lot of the stuff in the projects I want to make, but the boss enemy floats up to the top of the frame and out of sight. I can't figure out why, although I'm probably missing something very obvious. I'm going to attach the game file if anyone wants to take a look. I've changed it a bit from the tutorial (I didn't want a scrolling screen, a small window, or a panoramic view), but I've calculated all the expressions correctly, I think. What am I doing wrong?

What is the name of the boss enemy that is floating up?
I quickly ran the file but couldn't tell what I was looking for.

Sorry I didn't clarify myself too well.

It's just called Enemy 1. If you press "Enter", you can warp right to the end, which is how I discovered it was floating up, supposedly. You can see the torpedo detector (the little bluish box set to attach to it) going upwards, but the enemy itself never seems to appear. The enemy (a red sub) was never set to appear invisible, but the only indication that it's there at all is to make sure the torpedo detector is visible.

where did you get the tutorial?

Is line 10 in the enemy sub routine suppose to trigger continually?

negate - Animation Destroyed is playing

While I don't know if that is moving the enemy offscreen when I put a sound to play when this event was true it was triggering over and over.
One of my favorite debugging tools is to put a sound to play so you can "hear" when events are triggered.

Great tip! And thanks for all your help!

Kristopher, I got the tutorial here. It's a pretty neat way of getting to know various functions for different kinds of things.

Thank you.