When first starting this game I recommend just playing it for fun before trying to 100% the achievements. I am putting a disclaimer here that you will not be able to unlock the max abilities or get every achievement with just one play through. There are a few things that I would make sure you do in order to make things easier for you.

For starters do not panic if you don't get an achievement as soon as you finish a level. (This includes the tutorial too.) It will give it you once you start the next level. Make sure you try to pet every animal you can, including the cats, to make sure you don't have to play a guessing game at the end for what animal you didn't pet yet for the achievement. I will put a list of all the animals you can pet next to the achievement later in this guide.

For getting 100% on every map, that will be a challenge on some. They did release a patch yesterday after I had typed out this guide for all of the glitches. I do not know if they patched and fixed them but I will include the ways to get around them either way just in case. The levels I am referring to are Asia, Africa and Poland. The other important thing to note is that there is no way to track old levels nature completion and see which ones you will have to replay so I recommend 100% nature on every level you can during the first play through.

Below is a list of all of the achievements for basic collecting trash and water or using the sprinkler and hoover machine. There is no tracking system sadly for seeing your progression but I got all of these achievements during my first play through of all the levels.

For petting every animal here is the list with the level:
Railstation Level - You need to pet a duck and a rabbit.
Alps Level - You need to pet a sheep.
Iceland Level - You need to pet a puffin and a snow fox.
Forest Level - You need to pet a deer.
Asia Level - You need to pet a panda.
Australia Level - You need to pet a koala and a galah.
Beach Level - You need to pet a seagull. Also double check to see if you can pet a sea turtle. I can not remember if you can but double check while you are playing it.
Poland Level - The final animal that you need to pet is a cow.

This section will cover the basics for this the completion achievements. Once again for the 100% completion on all maps, there are some issues so please go to the section below that goes more in depth on the maps that will cause issues.

There is another guide that does give you the option to go into the game files and change the % of the nature completion rate which is what you need for 100% completion. If you want to try that you can go for it but it unfortunately did not work for me. This worked in my favor though as you will need 2 out of the 3 maxed abilities in order to finish this game with its glitches.

Asia
Asia is the easiest glitch to get around. With the way it was made, it can over the 100% nature mark and in the games files it will actually say 101% or 102%. Even though it is over 100% it still does not count that as complete for the 100% completion achievement.
With that being said the easiest way to get around this is to clean the first the small area you spawn in on and the 3 islands fully on this level. Make sure all the trees, plants, bushes, and bamboo are fully grown and there are no dirt piles left. Once you get to that last island, remove all the dirt piles and make sure you complete all the quests first. Then take your time with watering the remaining plants until it says in the top left 100% nature. Do not water anything else and proceed to the next level and leave. This should make sure it is saved at 100% and does not go over the mark.
(You may not have to do the quests before 100% completion for nature but I recommend you do this just to be safe.)

Africa
Africa is the most annoying in terms of trying to get 100% completion on. Now before getting into the 2 glitch spots on this level, I do not know if they have been patched with yesterday's patch but either way I am including it. You will need the 2 best upgrades in order to finish this level. You will need the one on the far left and the one in the middle column for upgrades.

On this level the first glitch spot but easiest one to get is inside the camper along the left side of the map. The easiest way to tell if there is a pile underneath it is by putting your sprinkler in front of it. If the sprinkler is spraying at the camper and you can't see anything then it is underneath it. You will need to place the sprinkler inside the right side of the camper in order to get it. You can check to make sure you got it by trying to suck up the debris. You can either use the hoover machine or by manually sucking it. Now to double check you have gotten it just place the sprinkler in front of it again and watching to see if it sprays at the camper.
Now I recommend getting the middle columns top upgrade in the menu that way you do not have to pick it up in order to place it again later on. This also makes it so you do not have to worry about potentially finishing the level without the sprinkler in case you can not grab it from inside the camper.

For the last spot it is right behind the scrap recycle machine and in between the tree and just above in the middle of the rocks behind the recycle machine. There should just barely be a water bottle or cap of one seen in the ground. You will not be able to get it with the sprinkler or the regular spray. I have seen people use the tornado some how on it but that method did not work for me. The method that worked best for me is getting the far left top upgrade that instantly destroys dirt piles and grows plants instantly. The method work instantly for me by aiming at the hidden pile in ground and by using that ability, I was able to clear it. Now unfortunately it does take 8000 to get this upgrade so I recommend going to back to replay the other levels you have either thought or know you didn't 100% the nature on them. That way this may be the final level you need for the 100% achievement.

Poland
On this level I only had one issues on but there is 1 spot that may be glitchy and an issue with finding what plants you may have missed for 100% nature.

For the glitch spot is where the tent is built on the map and some people have had trouble getting the dirt spots there. Now once again I would like to remind you not to do the quests until nature is at 95% as usually by that point there are no more dirt piles and the plants are left. I had zero issue with this luckily as I made sure I got all the dirt spots in this area before hitting 95% nature. If you do have an issue I recommend trying the sprinkler and trying it from different angles or in the worst case use the top left upgrade if it comes to that.

The second issue is that some of the plants that need to be fully grown do not show up when you press G to scan. The only way I was able to figure it out was by randomly placing my sprinkler around the map and waiting for it to spray at the something. The best way I recommend, this goes for all levels, is taking the time to hit every area little by little as you go around and take your time with every plant and dirt pile.

For the secret achievements I am going to list them out a give the best description I can of where they are. Unfortunately steam won't let me add those screenshots and images of their locations no matter what I do so check this guide out that has pictures included to help you.

https://steamproxy-script.pipiskins.com/sharedfiles/filedetails/?id=2904643821

Familiar Face
This achievement is on the Iceland Level. When you first spawn in there is a river on the left hand side. Follow that straight forward until you see the 2 trees and the rock formation where it ends. There on the rocks should be a little chicken that you can press E on to get the achievement.

Foreshadowing
This achievement is on the Asia Level. When you first spawn, before you cross the bridge, walk on the right hand side and behind a rock there should a llama to press E on to get the achievement.

Ancient Technology
This achievement is on the Australia Level. Behind the camper in the back of the map is where you can find the piece of ancient technology, press E on it and get the achievement.

I'm Human and Big Hat on his Hip
These achievements take place on the same level which is the Garden Level.
For I'm Human, the second island across the stepping stones is where you will find it. As soon as you cross the stepping stone there will be a stone pile connecting to the beginning of the stone wall. Parkour onto those and look over the wall to press E on the cow and get the achievement.
For Big Hat on his Hip, it is located in the back of the map right before the bridge leading you to the fountain. The best way to locate it is by getting to the patio with the recycler and painting, and they go to the brick wall to the front right and just to locate where it is behind the wall. You can click it by jumping and hitting E to get this achievement.

I hope this guide helped you on either a glitch or with 100% completion for achievements. Please let me know if you have any questions and I will try to answer them. Please do rate this or like this guide if it did help you. Thank you and have a great day!