To defeat Jazz with Megatron, first climb the building behind you. Then, attack all the turrets but do not destroy them. When all five turrets are badly damaged, go to one of the corners and attack the furthest one. After you do this, Jazz will send Autobots to attack you. Do not worry about them; just go to the next turret and destroy it. Continue doing this until there are none remaining. After finishing this, a cinematic with Megatron chasing Jazz will appear. When the battle starts, attack Jazz with your heavy weapon. This will be difficult because Jazz is always moving. However, it will do a lot of damage. Also, if possible, do not go toward Jazz because he will just jump away. If your health gets too low, look for the entrance to the Sector 7 underground base. If you see it, go slightly into it then start running and transform. You must use the afterburner or Jazz will shoot you. If you manage to get to the bottom, destroy objects until you find health. Continue this until you have full health then go back out and attack Jazz again. If your health drops again, go back into the Sector 7 underground base and repeat the process.