BLACKBOX: In the Cockpit of the Plane. Upgrade Tail a few times, go to the docks, and jump over it, to the left. Go inside the cockpit. SECRET PASSAGE: Go down, lower left tunnel. Go through the caves. At the top left, there's a little hole. Time it right and jump through. Sometimes a fish pops out and eats you. Be careful. MONSTER FISH: Go down, lower right tunnel. Go slow and approach the fish. After a pause, the fish starts chasing you. Lure it down to the mines, and try to go around the mines and explode the fish on one. THUMBS UP SO PEOPLE KNOW!
For those asking where the Black Box is: Go through the right tunnel, to the Docks. (You need to have upgraded Tails for this). Then, boost over the docks (to the left, in land). The cockpit of the plane is there. Go inside. Find fhe Black Box! :D
Suggestion: The Shield Drain for the Support unit should restore the unit's health as the enemy's health drains. Right now, I find it hard to stay alive. If I use the Mothership as a shield, my heal isn't strong enough to keep it alive. But I also can't live long by trying to avoid the enemy attacks.
Good game, only a few things I would improve: A 'Hard' Difficulty or set of levels. I found these levels a little too easy. Also, when you drag the screen, sometimes the game won't let you and it keeps focusing on the food. Usually happens when it's moving. This makes it hard for me to plan out my path or make quick changes to it. Overall, 4/5.