A Tower Full of Cats requires a lot of item acquisition and jumping between maps.
If you are looking for a more chillaxed ISpy/Puzzle game to achievement hunt in, I recommend:

• Hidden Cats in blank franchise
  
• 100 blank Cats franchise
  
• Cats and Seek franchise

With this guide you can expect to complete A Tower Full of Cats anywhere between 1-2 hours.
Best of luck and thanks for using this guide!


Acquired when you start the game, open the gate and accept the request from Leo the Orange Cat.


On the left side of the map you will see 3 little dots. If you hover your mouse over these dots they will expand with icons connecting to the different tower maps. By clicking one of these fast travel points you will unlock the achievement.

Unlocks upon entering the Pre-History Map.

Find all exterior cats of the Pre-History tower.

Find all cats in the cave.

Find all cats in the den.

Gather all hidden screws and nuts in the Pre-History Era.

Acquire the Magnifying Glass from NPC Lybica by clicking them.

Unlocks upon entering the Egypt Map.

Find all exterior cats of the Egyptian tower.

Find all cats within Bastet's room.

Find all cats within the pyramid.

Gather all hidden screws and nuts in the Egyptian Era.

Within the Pyramid, the Eye of Ra will be resting against the tomb.

Acquire the Axe by clicking on an axe sitting atop a cactus on the far left side of the exterior map.
This Axe will be used to cut down the foliage that sits in the Pre-History cave by clicking it.

Unlocks upon entering the Greece Map.

Find all exterior cats of the Greek tower.

Find all cats in the bathroom.

Find all cats in the library.

Gather all hidden screws and nuts in the Greek Era.

Tower Quest
As part of Lino's Quest, Collect all 5 scrolls hidden across the exterior of Greece.

Unlocks upon entering the Medieval Map.

Find all exterior cats of the Medieval tower.

Find all cats in the tavern.

Find all cats in the stairs.

Find all cats in the Labratory.

Gather all hidden screws and nuts in the Medieval Era.

Tower Quest
Find 20 cats that sit outside of the tower perimeter. The background is blue and when these cats are clicked they appear in gold/yellow.

Acquire the Lab Key from NPC Lily after completing her quest. This key unlocks the room on the far left of the Tavern.

Unlocks upon entering the Industrial Map.

Find all exterior cats of the Industrial tower.

Find all cats in the store.

Find all cats in the factory.

Gather all hidden screws and nuts in the Industrial Era.

Tower Quest
Collect all 15 fish scattered across the exterior of the Industrial Tower.

Acquire the Bag of Seeds from NPC's Pietra and Vivi to start the Tower Quest below.

Tower Quest
Click on all empty pots in order to grow a tree sappling, this achievement also ties into...
Click on all the pots that reside in the 20th century tower in order to plant tree saplings within them.

Unlocks upon entering the 20th Century Map.

Find all exterior cats of the 20th Century tower.

Find all cats in 1960.

Find all cats in 1980.
The hidden cats can be found by pressing the arrows on the top right of the TV to change the channels.

Find all cats in 2010.

Gather all hidden screws and nuts in the 20th Century.

Tower Quest
Collect empty bottles until the trash can in the middle of the map appears in a green color.

Unlocks upon entering the Future Map.

Find all exterior cats of The Future tower.

Find all cats in the control room.

Find all cats in the bedroom.

Gather all hidden screws and nuts in the Future.

After collecting all the nuts and bolts and finding every cat, Leo will be waiting for you at the top of the tower. After entering the tent, you will be tasked with a small mini game to build the spaceship in order to blast off to Felinus B and unlock the Messed up Era.


The ship should look like this if you arranged all pieces correctly.

This achievement should auto unlock when you repair the spaceship and speak to Fofino, travelling to Felinus B.

Find all cats on Felinus B (None are hidden, they are marked gold/yellow on this map)

On the left-hand side of the Felinus B map there will be a toggle meter/slider. Simply play around with that slider and the achievement should unlock for you.

Collect 20 of the hidden mice scattered across the Felinus B planet.
The mice look as follows:


After finding all cats on Felinus B, you should receive a call from one of the cats where they express concern that cats of different eras have escaped to the wrong timeline. You will have to play through a miniature version of the game again where 10 cats from differing eras appear on each map (including the hidden maps that reside within the main maps). None of these cats are hidden/special cats so they are fairly easy to spot and for such reasons I didn't include images here. Start your way from the bottom and go through each exterior/interior section of each map until you find every hidden messed era cat in order to acquire each of these achievements.

Unlocks after you talk with every NPC Cat from each Tower Era (Which you have to do anyways to unlock their quests and items to progress in the game)
Unlocks after you beat the game.

Unlocks after achieving all 69 other achievements in the game. I believe this is a Hidden Achievement.