Head forwards and take out the back row of guards first (ranged threat). You are quite big so it shouldn't be hard. Mop up and head up the slope. Dodge the missiles and continue on into the tunnel where you will beat up some robots throwing rocks. Knack will help himself up.
Head forward, break the door for relics, and take out the room of guards. Keep going to find another room then battle some robots (focus on the one throwing rocks). Head forward to see a scene (good moves, Knack!).
Head forward and break the relic box you see. From there head *south* and destroy the wall for:
HIDDEN CHEST #50:
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After the first cut-scene in this part, go forward and break a relic box. From there, go south and punch the wall you find to uncover this hidden chest.
Head forward now and you'll come to another "puzzle" room. Hit the switch and you'll see a maze. Follow the first path with a purple bot in it (the one on the right), then make your way to the left and down a bit before you can head up and to the exit. Easy.
Head forward to see a scene and end this (relatively short) part of the chapter.