So in this guide I'm going to show screenshots for the location of every coin in the game and give a brief description of how to get the coin. I'll be putting the coins in order of when you might come across them in a standard playthrough and state any items required to get the coin.
If you need help finding specific items, please look at my other guide:Solution for COLLECTOR in MinitCoin 1: Starting House - No Requirements
Just break the pot in your house.
Coin 2: Hidden in Snake Tunnel - Flashlight
In the Snake Tunnel there's a false wall. Go through the false wall and you'll find yourself in an invisible maze. Push left and you'll find another room with a chest and coin in it.
Coin 3: Underneath Quicksand - No Requirements
There's a quicksand pit one screen west of the Desert Campsite. The quicksand pit spans two screens, it's easiest to get the coin if you sink in the southern screen. Once you fall through, there's no way out and you'll run out of time so make sure you got the new house first if that's where you want to respawn. In the pit you'll find a treasure chest with a coin. Be careful of all the scorpions in the pit once you fall through.
Coin 4: Dumpster by Sneaker Hut - No Requirements
There's a large dumpster near the Sneaker Hut. Just hit it with your sword a coin pops out.
Coin 5: Hidden Part of Warehouse - No Requirements
There's a hole in the wall near the Sneaker Hut. Hit it with your sword and a secret entrance opens up. Inside there's a chest with a coin in it.
Coin 6: Desert Ruins - No Requirements
If you travel around until you get to the screen that's directly north of the Sneaker Hut you'll find a sign that points east towards "Ruins." Travel east a few screens and you'll find a broken down truck. Near it is a chest with a coin in it.
Coin 7: Lost Temple East - Watering Can
If you use the Watering Can on the fire in Lost Temple East, you will enter a room full of fire and bats. The goal is to make it across the room with full health. If you do that, the door will be open and you can find a chest with a coin. If you get hit, you'll have to start over on a new respawn.
You now have enough coins to buy the Fast Shoes at the Sneaker Hut on Normal.Coin 8: Storeroom of Hotel - No Requirements
In the back of the Hotel is a Storeroom that has a chest with a coin in it. Just walk into the back of the Hotel building where the door is and you'll be in the Storeroom. Push the boxes out of the way and you'll get your coin.
Coin 9: Defeat Woods Gang Three Times - No Requirements
After you save the Hotel Guest from the Woods Gang, you can keep fighting them. You'll have to defeat them three times to get the coin. Each time you defeat the group, you'll have to die and respawn. Each time you fight the, there will be an additional guy to defeat.
Coin 10: Inside the Waterfall - Flippers
On the same screen as the entrance to the Snake Cave, there's a Waterfall. Use the Flippers to swim into the Waterfall and there's a chest with a coin inside.
Coin 11: Peninsula Near Land Fish - Flippers
If you go near the land fish by the Tavern, you can see a little ramp near the ocean. Swim over to the ramp, follow the path, and you'll find a chest with a coin in it.
Coin 12: Coin in Sewers - Flippers
There's a pot on the right of the screen with the Tavern. This pot needs to be hit three times to be destroyed and reveals an entrance to some sewers. Follow the sewers north and when you find the exit, follow the stream to find a chest with a coin.
Coin 13: Island Through the Sewers - No Requirements
Go into the Sewers the same way you did for coin 13. Where you find coin 13 is a staircase out. Take the stairs and you'll find yourself on an island with a chest and coin.
Coin 14: Treasure Island - Flippers
If you swim to the Treasure Island the Old Man by the Lighthouse talks about, then you will find this coin (along with a tentacle). From the Lighthouse swim one screen west and then swim south until you find the island with the chest with the coin in it.
Coin 15: Lost Temple North - Basement Key
To clear Lost Temple North you have to SPAWN from a house and die in the room, then you have to do that for each of the four houses. When you successfully do this, another group of trees grows depending on which area you died from. After you have done this from all four houses, the door will be destroyed and you can get the coin (which is technically in the basement of the Sneaker Hut).
Coin 16: Waiting in Complaint Line Inside Factory - No Requirements
South of the main desk in the Sword Factory is a complaint line. Stand at the end of the line long enough and the tree will turn into a coin. If it doesn't work for you the first time, get there with more time on the clock.
Coin 17: Boring Tunnel in Factory - Press Pass
In the southern part of the Sword Factory there's a room with a large boring machine. Hit the two arms to release the machine and then hit the machine to turn it on. It'll create a large tunnel with a coin in it.
Coin 18: Back of Truck in Factory - Press Pass
Inside the warehouse of the Sword Factory is a truck that you can get into. In the back of the truck is a coin.
Coin 19: Mine Near Factory - Grinder
After you get the Grinder, you'll find a box in the mine that is in your way. Destroy the box, go south, and follow the convyer belts until you find the chest with the coin in it.