These you'll 100% get on your first playthrough
A less than perfect day...
Witness a small demonstration of Risky's power.


All it took was a positive attitude!
Complete Chapter 1: Lost Relics


Facing an EPIC CATACLYSM!
Complete Chapter 2: Molten Mix-Up


Good Deeds
Complete Chapter 3: A Royal Pain


Sequin Land is safe!
Complete Chapter 4: Risky's Fault

You'll get these after buying certain items and maxing out Fireball, Pike Ball, Storm Puff, and Shampoo.
Firestarter
Purchase Fire Max


Shocker
Purchase Storm Max


Sphere Hunter
Purchase Pike Ball Max


Speedster
Purchase Pants Ants


Out of Sight
Purchase Vanish


Walking on Air
Purchase Float Cake


Double Trouble
Purchase Twin Mint


Money Moves
Purchase Greedy Jar


Coin Collector
Purchase Attract Up


Powered Up
Purchase MP Saver


Hair Care
Purchase Shampoo EX

All of the transformation you'll get throughout the story. As for the upgrades, some of them are missable.
Get Crackin'
Obtain Crab Form


Shell Shocker
Obtain Crab Flint

In Orc Orchand, to the right of Sky there's a pond, drop down, blow a wall to the right

Hold on Tight
Obtain Monkey Form


Magical Monkey
Obtain Monkey Vision

In Naga Cliffs

Faithful 100%
Obtain Elephant Form


Stomping Ground
Obtain Elephant Tote

In Haunted Grove, in a cave at the left edge in the background

Great Power
Obtain Spider Form


Great Responsibility
Obtain Spider Venom

In the last room of the Museum head up

Under the Sea
Obtain Mermaid Form


Bubble Blaster
Obtain Mermaid Bubble

In Haunted Grove, in a cave in the foreground, right to the ground switch


Fly Me to the Moon
Obtain Harpy Form


Unfriendly Skies
Obtain Harpy Talon

Found in a first cave right to Sky, in Haunted Grove

It's grinding time!
Where you truly live!
Collect All Heart Holders
1st Heart Holder is in the cave to the left of the first background portal

2nd Heart Holder is in the cave right of the Crypt (crab form is required)

3rd Holder is in the cave in the middle of the foreground (requierss Monkey Form)
4th Holder you'll get by giving Lost Game Tape to the wolf in the Mining Town, which can be found in the cave in Orc Orchand.

5th Holder can be found in a cave in Naga Cliffs (requires elephant form)

6th Holder is obtained by giving Pocket game tape to the wolf in Museum Town. Tape is located in Naga cliffs, in a cave in the sky hidden behind stone (requires Harpy form or Float Cake)
Final Holder you get, once again, by giving the wolf in Bog Town Classic Game Tape that can be found in Haunted Grove, in the far left cave in background (Requires Stomp)

Safe Squids
Collect All Secret Squids

As said by NPC in Scuttle Town there are 3 Squids in each Open Area (Orc Orchand, Naga Cliffs, Haunted Crypt), 3 in each Crypt, and 5 in each Labyrinth. The rest are located in Puzzle Caves.


№1
Up on this pole
№2
Above Shantae's lighthouse
№3
Under the bridge to the right

The first squid you'll ever get. Unmissable
№1
Above first frog dude
№2
After returning Scuttle town back to normal, drop down and to the left
№3
In the same spot, above this lantern

Starting with Crypt
№1
In the first room with a bomb, blow these blocks, squid is behind them
№2
In the next room, blow a block hidden in the wall
№3
After obtaining the carb form you'll find 3rd squid in the roof after water corridor
№4
After leaving the crypt head left, to the foreground, left again till this place.
№5
Then, go right to the cave with diving spot, use crab form and go to bottom left
№6
Head to the Labyrinth, the first squid will be in the hole after first key, aim left while falling.
№7
Second squid is right after the first steel door(Pike Ball and Monkey form are required)
№8
Third Squid in the center of the room with floating pettles
№9
Fourth Squid is the room left of the pettle room (Monkey form is required)
№10
Final Squid is in the room after Fountain, where you head after obtaining monkey form
№11
After leaving the labyrinth, head right, till this spot
№12
Return to foreground, find this spot
№13
To the right of Sky, there's a pond, in there blow a block in the wall

Squid is located above the huge lady statue

Stomp under the fourth painting
№1
№2
Break purple blocks on the left and climb
№3
№4
To the right of Sky, climb this wall
№5
№6
№7
After parkour with spikeballs, head up on this spot
№8
№9
№10
№11
At the far right edge in the background
№12
After getting Mermaid form and Mermaid Bubble return to the cave where you got Monkey Vision

Dash through the wall on the right in Elephant form

№1
Above the palace
№2
Stomp under this gem
№1
№2
№3
№4
To the right of Sky there's a pond, head down left
№5
In the cave where you get Mermaid Bubble, take a different rout to find a squid
№6
In the cave with a Classic Game Tape, there's a hidden breakable floor (requiers stomp)
№7
After shifting the ground, this squid will be available
№8
On the 3rd floor, here head up, continue till you find this drop. Break the wall with elephant dash
№9
On the basement level
№10
Fly up in the second column of floors
№11
On the 4th floor with 2 locked doors
№12
At the end of the same room as previous squid
№13
On the foreground, on the left side of the map

Fortune and Glory
Obtain 100%
Collect all Heart Holders, Secret Squids, all Transformations and Upgrades, and buy all items from Rottytops' Shop.

Master of Unlocking
Obtain all win screens


Any Speed, Any %
Any Speed, 100%
Speedrun, Any % - under ~2 - 2,5 hours
Speedrun, 100% - under ~3,5 - 4 hours

I'm not sure about exact numbers here, but i got 100% speedrun at 3,17 hrs and any % speedrun at 1,57 hrs.
Also, this achievement is bugged, as you need to get all winscreens in one sitting. After getting any% speedrun i had to replay my 100% speedrun save once more to get the achievement

Trendy Traveler
Complete the game with an alternative costume.
After getting all 50 Secret Squids you'll get Beach outfit (which is basically good old magic mode). Deluxe edition costumes also work for this.