Here is the full list of all 25 Creature in the Well achievements.
Hit 20 bumpers with one shot
Get thrown out of the machine
Generate 1,000 power in one hit
Help Roger mop the floor
Find a secret charge tool
Let's play
Open the temple
Try to escape the sandstorm
Find a secret strike tool
Upgrade your BOT-Core
Activate the Power Reserves
Unlock the Support Monoliths
Unlock the Weather Control Monolith
Enter the Creature's well
Save Mirage from the sandstorm
Find all the lore
Heal a total of 1,000 health absorbed from anomaly balls
Destroy 100 drones using EMPs
Charge 7 orbs at once
Fully upgrade the BOT-Core
Find all of Danielle's tools
Find all capes
Find the scavenger's hidden stash
Find Phillip's prototype
Generate a total of 2,000,000 power