The fracas at the top of Alden's tower wasn't the boss battle for the Warren; you've still got to fight the big bad guy himself. First, you have to catch up to him by making your way along the girders of the bridge. Step carefully and take out Dust Men as they pop up. You can use the girders for cover by hanging from the edge. Use Precision or Lightning Bolts and avoid Grenades or Hammers as they will mostly be wasted.
Finally, you'll reach Alden who will fight you from inside a giant trashbot. This trashbot is bigger than the others you have faced, but not much different. The fight is in three phases.
The fight[edit]
- Phase 1
Alden hurls trash meteors at you. Dodge them or Shockwave them away and unload Lightning Bolts on the bot in between. When the bot is stunned and its mouth opens, quickly shoot Alden.
- Phase 2
Alden sends a swarm of scorpions to play with you and mixes in a machine gun with the meteor strikes. Use Polarity Wall to deflect the machine gun and Shockwave to deal with both the meteors and the scorpions. Continue shooting the bot as before and shoot Alden when the bot's mouth opens.
- Phase 3
Alden sends even more scorpions over and now starts hurling fireballs. The fireballs burn for a bit of time, but this also helps with your bug infestation, so it's not bad. Just keep dodging the fire or use Shockwave on the fireballs and use Lightning Bolts as before until the bot is stunned again and you can shoot Alden for the last time.