Mission 3:It Fell to Earth!

Once a seven of diamond is down, the Horror and Adam Zorn will arrive. At this point the other two will race across town to a teleporter, and its brownie points for you if you can stop them.

Biff will tell you two useful things by analysing the Horror:

1) It changes form depending on who's closest. Every 5 seconds it checks: Adam Zorn -> speedy bullet form, DD -> long thin energy form, King Zero -> big defensive form.

2) It heals itself if hit whenever cars or lamposts are in the area. This can be seen as a blue sparkle around the metal items and the Horror itself, causing it to heal half the difference between its current health and maximum.
So, its literally unkillable until you clear the area of cars and lamposts.

If you know these, just keep him at a distance and ignore him.

Your best chance of taking out the sevens is to send Adam Zorn after them using multiple teleport hops (never make this guy run anywhere!) - he'll take them down in one go. Also, get him away from the Horror as soon as he lands - it has a tendency to fire of an area attack that'll stun him if you dont.

Take the Horror down using AZ from a distance, KZ close up and DD cloning it. DO NOT clone it in big form or they'll both start using the area attack. This also forces it to switch between energy and big form, whereas the speedy form is the most dangerous. If it does assume this form, freeze or hypnotise it - its pretty much immune to Adam's blasts.

As for clearing the area - use DD to do this with Hell's Gate. If push comes to shove she is expendable on this mission.

Finally, get used to the analyse command. You'll be seeing a lot more of it.