World 1-1: The Beach
The first level is a straight run to the right, jumping over platforms as necessary.
In the first area, you can swim to the left as Penny to collect the first Rubber Arrows. Continue to the right to proceed.
When you reach the broken set of platforms, there is water underneath where you can use Penny to swim to collect another set of rubber arrows. You will need to use Brain to get past the area, by either double jumping from the water or with a fast-running jump.
The extra live in this area is accessible in the bottom-right corner; if you have no inclination for it, simply jump along the upper path to the exit.
World 1-2: The Jungle
The first section has a few items and points. To contine, head to the bottom-right; if you hit the water, switch to Penny to allow jumping out to the lower-right corner. Once there, wait for the platform to arrive, or double jump across.
On the right of the chasm is a set of ledges that can be used to jump up.
Head to the left, climb the ladder, and reach the exit to the right.
World 1-3: No Man's Land
Below the starting area is a few weapons that can be collecteed; you will have to jump on a metal box to get them.
Proceed right of the starting area to the right-edge of the map. Climb up the laffer, and jump on the box to activate a moving lift.
On the next platform, you can head up and right to retrieve a 1-up (visible by jumping on a box). Otherwise, head left to continue. Jump up the platforms until you see the ladder, and head right.
Plant the explosives and have Penny hack the computer.
Boss
Once you hack the computer, you will encoutner a first boos in the mad-cat face statue.
- As Inspector Gadget, jump over the mines, and hit the enemy when he peeks out of the eye. Jump away before the statue electrifies itself.
- The statue will also fire a missile periodically, which flies into the sky then drops down. The missile damages Gadget by about half of his health bar.
After a few hits, the villain will fall out of the statue, and you can proceed through the gate.