Sebastian Krist

Hint 1 of 8:

Krist is fast, fires missiles, and shoot mines at you.

Hint 2 of 8:

When you go in to Sebastian's room, clear the area of bad guys, or, have
Krist do it for you.  He has a bad aim.

Hint 3 of 8:

Now, the thing is to run back and forth in the room.

Hint 4 of 8:

At the end of each side, there are several heal power-ups and healing basins.
 Refill your life here.

Hint 5 of 8:

There are weapons scattered throughout, so hunt them down.

Hint 6 of 8:

The key to killing Krist is to run around until you find him.