Walkthrough

Grunt Description of what to do
Bare-handed #2 Go get the Tool you see in the southwest corner of the "baby bear sized" water pool.
You almost certainly will have to give the enemy Grunt lurking there something to play with, in order to acquire the implement.
Shovel #2 You probably got 'nicked' by a "butter knife", so a Bottle of Zap Cola would be nice.
You don't want him anywhere near you, if that distraction provez faulty.
Perhapz you could trap him in a corner ... and then scram(!) while he starez at the piece of junk? (On the far side of the Green Toggle Switch (GTS) would be a good place to wait.)
If you looked around, you noticed that several Green Pyramidz (GP) were lowered , while some that were lowered were raised .
Does that suggest anything to you? Such as a future task you will need to fill?
When the BPz are lowered , he activates the STS and observes.
When satisfied he knows the way, he does it again and divez through the Blue Wormhole (BW) ... and finds himself joining his two buddies.
GooberStraw #1 Turn an enemy grunt into a Goo Puddle .
(Thank the Designer for providing you with refreshmentz .)
Use the tool as intended to begin filling the Goo Well (#1 of 4 required).
Step on the Black One-Time Switch (BOTS), to see what it does.
Go add enough Goo to fill the Goo Well, and bake another teammate.
Look around, and pick up some loose change (Coin #1).
Go stand under an Arrow , and when told to do so ... step on it!
Shake it off, and go step on another BOTS . Don't just stand there!
Stroll back down to the Arrow and cross it again, this time painlessly.
Go back to the Landing Dock (LD) next to the GruntCreationPad .
(And be glad you did!)
You get that floating feeling, as the ground seemz to open up under you.
You land next to two Coinz (Coinz #2 & #3) ... and pocket them.
Stomping around, you may hear a click. (Good job!)
Then dive into the Red Wormhole (RW) and return to the LD .
Go in search of something to suck up. (Won't help, though.)
Bare-handed #3 Pick up the Tool right next to where you entered the game.
SpongeGun #3 Join GooberStraw #1 and take a shot at an Arrow and tell him to "step on it!".
When the Black Pyramidz (BP) to the east are lowered , take a few stepz in that direction and pop the enemy Grunt once ... onto a Blue Hold Switch (BHS) and notice some Bridge Tilez rise .
Go downstairz and enter into an "artillery battle" with a different enemy Grunt and turn him into a Goo Puddle .
There are three enemy Gruntz paddling around in the "momma bear sized" water pool.
There is a GTS nearby, but you can't get through the tree to it.
Can you get to it "the long way 'round"? Sure ... those guyz are friendly ... NOT!
More "artillery practice" can eliminate the problem(z) ... but where?
Perhapz you can encourage them to make their "last stand" on land, ending up as quivering Goo Puddlez (possibly of use to your buddy GooberStraw #1)? ... or just spread around, soaking the ground.
Three out of four ain't bad, but can you make it four out of four?
Do you even want to take the time to try?.
Is there anything a fourth Grunt can do to help the team?
You should eliminate (some of) the three "bad guyz", to make getting to that GTS easier (yes, you can turn all three into useful(?) Goo Puddlez).
Right now (before you do anything rash) is a good time to SAVE!
'Encourage' the enemy Grunt to take a ride. Wow!
SpongeGun #3 & GooberStraw #1 Find their way to their CheckPoint Switchez with help from Shovel #2.
SpongeGun #3 Enters into another "artillery battle" with a different enemy Grunt and turns him into a Goo Puddle .
SpongeGun #3 & GooberStraw #1 Either Grunt can now collect the four Coinz .
It is difficult to avoid the BOTS ... don't even try!
Either Grunt can investigate the strange Switch.
SpongeGun #3 enters into another "artillery battle" with a different enemy Grunt and tries to turn him into a Goo Puddle . (Chances are he fails ... out of range.).
In doing so, he crossed over a Silver Timer Switch (STS).
You may be able to observe what happens, for use when someone goes down there.
Shovel #2 When the BPz are lowered , he activates the STS and observes.
When satisfied he knows the way, he does it again and divez through the Blue Wormhole (BW) ... and finds himself joining his two buddies.
Warpstone Carry the Warpstone Piece to the King!