Chrono Trigger/The Factory Ruins

Chapter 7: The Factory Ruins (2300 A.D. first time)

The Factory
You'll need to pick Marle or Lucca to accompany Crono and Robo, I personally prefer Marle because she has the Aura spell. Anyway, three security robots patrol the front hallway. After you've dealt with them, you can take the left or the right passage to the lab or the factory proper. You'll probably want to head into the factory first, although if you feel like cheating you could skip it all together.

On the factory side of things, search the room for chests, including one hidden in a passageway that seems to go nowhere, check out the conveyer belt to the south. Your goal will be to cross over it to the left, without bumping into any of the robots. If you touch a robot you'll have to go through a long series of fights before you get back where you started. I find it easiest to wait until a group of two robots has gone by than run as fast as I can until I reach an alcove. Keep making it all the way to the end, and you'll reach a new area where you'll fight some bugs. Cross a walkway, and go through the right door to learn the two codes which control the crane, XA, and BB. Go through the left one to reach the control panel, and enter the codes to open up a path to a new area and back to the start so you won't have to repeat the conveyer belt sequence. Head to the left and go through the door to pick up a bolt sword for Crono, and learn a password I could have told you anyway. Go back to the elevator and head out, and go down the other elevator this time to the lab.

In the lab, kill the acid creatures to activate the computer and open the hatch to the next level. Head to another computer on the next level to deactivate the lasers, and fight off some more acid creatures, while picking up some helpful armor and weapons along the way. Head down another ladder or take the elevator to get to a computer that requires a password, "XABIE."

Regardless of whether or not you completed the factory portion of the place, you can just enter in the code "X-A-B-Y" to skip to the last part of the level. Robo will flip a switch and you'll need to escape the factory before it goes haywire. You'll eventually come to the long walkway with robots, and Robo's old buddies will beat him up and take his lunch money. Crono and whichever partner you picked will need to take on the six robots. Crono's Cyclone technique works well, and have the other partner heal or provide support. You'll rescue Robo and piece him back together with Lucca's help, before heading off together into a time gate.

Challenging Lavos
Impossible during this stage of the game since you have no access to a time gate.

Continue to Chapter 8: The End of Time (End of Time)