When you move up to the open area at the top of the hill, another checkpoint registers, and the final horde of enemies appears on the wall ahead: 3 archers, plus 3 warriors with swords, followed shortly after by 3 more warriors, then 2 pikemen with shields. Because there are so many in this group, I find it helps a lot if you put some distance between them and Lara, so you can deal with them a few at a time.

I like to try and take out one or two of the enemies as they appear on the wall. You can also wait until they drop down near the red balloon...

...and then blow it up.

Or, run back down the sandy path to the area with the big boulders. This provides shelter from the archers—temporarily anyway.

Then you can fight the warriors close-up as they come to you.

By the time the archers arrive, you should be ready to deal with them.

A well-placed grenade can take out several archers if they're grouped close together.

If you need more space to maneuver, you can run all the way back down the fallen column to the lower area, or use the various buildings in the upper area for cover and to replenish your ammo. Just don't linger near the explosive balloons or let the Oni corner you in a tight spot. Better to keep moving, use Lara's speed and agility, and finish off the bad guys one or two at a time as they manage to catch up.

Use the buildings for cover just like you did in the beginning.

When the bad guys come around the corner, blast them with the shotgun. (Here I'm using Incendiary Shells, which I unlocked a little while back. Press the same weapon selection button multiple times to cycle through the different available ammo types, as described on the Controls page.)

The last few guys to appear should be the 3 warriors with swords and 2 pikemen with round shields. You may be able to pick off some of them as they come down the hill. Again, wait for them to approach the explosive balloons and then detonate them.

Like so.

The pikemen are the slowest, so you can try and injure them by shooting at their exposed parts as they move toward you. If they do manage to get close, use the Dodge Counter/Dodge Kill as described in part 1 and part 2.