Chapter 4: Fire and Water
Enter into the sewers to start the Chapter 4. Starting off you have to break the bridge with Nancy’s aluminium bat and pass through it. You’ll notice a gnome at your right that you’ll manage to collect only after advancing a bit. Break anything that‘s breakable and collect some health hearts and throwing stones you’ll find around. Take a ride on the water at the right side beyond the first bridge and climb at the first bridge you’ll face on this direction. Eliminate the enemy ahead and then adjust the water stream with the wheel you see above, you can even use the slingshot to make it spin. Now that you can pass on the right side of this room, make sure to extinguish the attacking rats without being harmed. After finishing off, use Nancy to go past the tunnel on the right. You’ll face other three dangerous rats that you’ll have to take care of.
At the end of this passage you’ll find the first of five collectible balloons. Go back, at the room you once turned the stream off and continue at the entrance above. Once you enter you’ll face an enemy plumber and a rat. Go straight and make the proper adjustments at the stream wheels so you can cross the canals on the right. After reaching the end on the right use Lucas’ slingshot to collect the balloons below and then continue below where you’ll find a green keycard. At this point go left by sliding into the water. Go at the beginning where you first started riding water and move to the top until you have reached the left bridge. Now use the keycard you just found to open this door and enter. You’ll face two hard-to-kill soldiers and you must react quickly.