I'm trapped! How do I get off the island with the ship!

You can't go back the way you came, because the blocks are too high.

And, on the other route, there's one gap that the cube just won't take you
across.

Remember the beast you saw when you first got onto the island?

You'll be needing his help.

Once you beat the space marine, get his device and use it.

Look at the back monitor.

Hmm ... looks like a missile launcher to me.

Arm one of the missiles, and fire.

This will distract the monster, and he'll go to check out the explosion.

Once he gets close to the explosion, the monster will look up and raise his
arms.