Let the Scorpion King to charge the pillars and hit his tail each time. Next, let him charge you again and attack from behind. Stand still until he gets mad and attacks with his super-slash. Run around behind him and hit his tail. When he drops, hit him in the torso. Repeat this process until he climbs the pillars again. He will attack again. Let him charge and attack from behind again. Wait as before, but longer. He will try to grab you. Move out of the way at the correct moment. He will get stuck. Hit his tail again, and then his torso. Repeat this until he climbs back up the pillars. Jonathan or Meela will bring the Spear of Osiris down and fail at trying to spear the Scorpion. Use the same tactic to hit his tail while he is stunned then get the spear and attack him.
Full health with Imhotep
You can acquire full health for Imhotep without using Soul Suck. Play as Imhotep on the British Museum level. As you are going to get the Resurrect Spell inside the Canopic Jar, you should see a glass container with a snake and scorpion inside it. After you obtain the spell, return to the container. Break open the glass. Then, while facing the scorpion and the snake, use the spell. Three Health Ankhs will appear. Collect them and you should have full health.
Invincibility
As Rick O' Connell, successfully get to Ahm Shere and go to middle of the place. Then pause game play and press Up, Down, Left, R1, R3, Triangle. You will return to the level and your energy bar will go up and remain there.
Playing as Imhotep
When you are Imhotep and find the Curse Of Death, do not bother wasting life using the curse on Bosses. It does not work.
Walk on swamp
When you are Imhotep, go to the swampy place in the jungle. For this part you will need to have to raised the block in the swamp. When you have jumped on to it (as Imhotep), use the Apis Spell. Run off the block and you will be walking on the swamp for a short amount of time. Note: Do not attempt this if you do not have much energy left. Also, do not use the Curse Of Death.
Defeating The Scorpion King...