To get this achievement you must do the following:
-Beat the game in under 2 hours.
As a rule of thumb, do this one in Pirate Mode (unlocked after clearing the game once) as you'll start with all the Pirate Items, allowing you to save a lot of time by being able to collect anything as soon as you reach it (barring parts blocked by story events).
Also, as this does not require you to get all the Dark Magic, you won't have to do the True Pirate Master battle.
Walkthrough, minimum path instructions. (The times are my checkpoints along the way)
Intro
Scuttle Town
-Library Card (from Sky)
(00:06)
Scuttle Palace Front & Sewer:
-Get 3 Flesh Pops (Drops from Snakes in Sewers)
-Get Travel Brochure
-Turn in Flesh Pops to Bolo for Gate Key
-Turn in Travel Brochure to Squid Baron for the Squid Oil
Scuttle Palace:
-Get Forbidden Isles Map
Saliva Island
-Get Metal Ring
(00:11)
-Get Ham Stink
-Use Metal Ring to get up to Lummox
-Drop down to get Petrify Spell
-Give Petrify Spell to Man
Saliva Island Cave
-Get Key to open door to reach Cyclops Plant
-Defeat Cyclops Plant for Spiderweb Island Map
Spiderweb Island
-Get Fossil
(00:21)
-Carry Rottytops through maze; this can be a potential time sink, so make sure to only do it in a single run! (See my guide for that to speed through it:
https://steamcommunity.com/sharedfiles/filedetails/?id=22797...)
(00:27)
-Give Squid Oil to Poe to get the Shriveled Thing
-Use Shriveled Thing to gain entry to Spiderweb Island Cave
Spiderweb Island Cave
-Get the Key in the top-right of the cave and open the door leading to the Empress Spider
(00:31)
-Defeat Empress Spider for Tan Line Island Map
Tan Line Island
-Get X-Ray Specs
-Get Mummy Sketch
-Get Enchanted Blade
(Return to Saliva Island)
-Get Mummy Sketch
(Return to Scuttle Island)
-Get Mummy Sketch (Now you have the Password to the Tan Line Palace)
(00:43)
[Trade Heart Squids for Hearts, if you want and have enough]
[Quick shopping for upgrades/items; especially Shampoo and Silky Cream]
(Return to Tan Line Island)
-Enter Password to Tan Line Palace
-Sneak through the Palace, collect 3 Keys and free Rottytops, Sky, and Risky Boots to get the Golden Pickaxe.
-Give the Golden Pickaxe to workers to clear the way on the island and access Tan Line Island Cave
Tan Line Island Cave
[Warning: Don't try to Boot Dash through the crushing room, it's too long]
(00:58)
-Defeat Squid Baron for Mud Bog Island Map
(Return to Scuttle Island)
-Trade Fossil and X-Ray Specs for Death Mask
[Trade Heart Squids for Hearts, if you want and have enough]
[Quick shopping for upgrades/items; especially Shampoo and Silky Cream]
(1:07)
Mud Bog Island
-Use Death Mask to enter City of Lost Souls
(1:11)
-Get Green Coin (Cannon Jump through ceiling), Blue Coin (Scimitar Drop back down), and Red Coin
(1:15)
-Give coins and beat the Color Trio to get the Golden Locket (This is a potential time dump, so be sure to save next door)
-Give Golden Locket to "Rottytops" for the Hopeful Flame
-Use the Hopeful Flame to get the Manly Musk
-Use Manly Musk to enter Mud Bog Island Cave
(1:17)
Mud Bog Island Cave
-Solve Elevator Puzzle (have to do a lot of traveling in a big circle through the cave to be able to do) OR use the Risky Boots Dash Glitch to just bust through
(1:18) [Yes, I used the glitch]
-Defeat Dagron to get the Frostbite Island Map
-Get Lost Soul from "Manly Musk Man" (Automatic, can't miss)
(Return to Spiderweb Island
-Talk to Rottytops to identify Lost Soul as Spirit of Joe
Frostbite Island
-Meet Ammo Barron & Techno Baron
(1:26)
-Get the Targeting Module from Bolo
(1:30)
(Return to Scuttle Island)
-Talk to Ammo Baron
-Give Spirit of Joe back to Joe
-Give Enchanted Blade to Brandon
-Talk to Ammo Baron to fire the cannon and open the Frostbite Island Cave
[Trade Heart Squids for Hearts, if you want and have enough]
[Quick shopping for upgrades/items; especially Shampoo and Silky Cream]
(Return to Frostbite Island)
Frostbite Island Cave
-Gather two Keys before opening the door to reach Steel Maggot, grabbing the third along the way.
-Defeat Steel Maggot for the Lonely Grave Map
Lonely Grave
-Witness the unleashing of the Pirate Master kidnapping Risky Boots
(Return to Scuttle Island)
(1:43)
-Trade in any collected Heart Squids for extra Hearts and do any needed shopping (especially Bubble Shields) for items or upgrades you need for the final battle (Especially Shampoo and Silky Cream).
-Head to the now-renamed Pirate Master's Palace and enjoy his difficulty-spike maze of death (OR use the Out Of Bounds glitch to just fly up to the final door leading to the big fight).
(1:44) [Yes, I used the glitch]
-Beat up the Pirate Master and enjoy(?) the Bad Ending and your Achievement!
My final clear time:
-01:48:11
Total collected:
-14/32 Heart Squids
-1/20 Dark Magic
Glitch List:
-Risky Boots Dash: Using the D-Stick and D-Pad, hold one in the opposite direction of where you want to Dash and tap the other in the correct direction. Tap several times and when you hear the tone, DASH!
-Out Of Bounds Flight: If you are Boots Dashing into a transition area (such as the door beneath the Pirate Master's Maze), you can pull up the Item Menu and eat something, canceling the transition animation and suddenly launching you upwards, only able to move left/right. If you don't go through a doorway, you will rise infinitely and have to reload your save.