If you’re just stepping onto Seashell Island for the first time, you’re in for a treat.
Under the Island is a 2D top-down action-adventure that wears its classic Zelda inspiration proudly, mixing clever puzzles, quirky humor, and a surprisingly deep world full of secrets.
You play as Nia, a teenager who gets dragged to Seashell Island while her parents conduct research.
Together with local girl Avocado, you discover the island is destined to sink beneath the ocean unless you can find four mechanical gears hidden across its many regions.
It sounds simple enough, but Under the Island has a way of making you feel totally lost if you don’t understand how it works.
This guide covers everything from exploration basics to combat, upgrades, secret-hunting, and all the stuff the game doesn’t bother explaining to you.
How Progression Works in Under the Island
The biggest mistake new players make is expecting Under the Island to be linear. It’s not.
The game follows a classic Zelda-style loop that goes like this: explore a region, find a dungeon, gain a new tool, then backtrack to open previously blocked paths.
Six distinct regions make up Seashell Island, including forests, beaches, snowy mountains, swamps, desert mesas, and underground caves.
They’re all interconnected, and you’ll be traveling between them constantly as you unlock new abilities.
Progression gates come in many forms.
You’ll find holes you can’t cross, boulders blocking paths, switches you can’t reach, burnable vines, dig spots, and water obstacles.
If a path feels impossible, you almost certainly need a tool you don’t have yet. Mark the spot mentally (or take a screenshot) and move on.
The main story is built around collecting those four gears from major dungeons scattered across the island.
But between those main objectives, there’s a massive amount of optional content that’s absolutely worth exploring.
Essential Settings and Map Tips
Turn on map location names immediately. This is the single most important tip in this entire guide.
Location names are turned OFF by default, and toggling them on instantly fixes most of the “where am I supposed to go?” frustration that plagues new players.
The in-game map doesn’t track your position well and doesn’t show fine detail.
There’s also no quest log or map marker system, which means you need to be your own cartographer.
Mentally note or screenshot blocked paths like cracked walls (bombs), suspicious ground (shovel), unreachable switches (Hiku bird), and burnable plants (Fire Plant).
Fast travel exists but must be unlocked at each location by solving a block-pushing puzzle underground.
Always prioritize solving these when you stumble across them because they save a huge amount of backtracking time later.
Talk to NPCs back in Koala Village regularly. Several of them will point you toward your next destination, which is extremely helpful in a game with zero quest markers.
Every Tool in the Game and How to Really Use Them
Your hockey stick is your main weapon with a standard three-hit combo.
The range feels short and awkward at first, but it gets the job done.
Upgrade its damage when enemies start feeling spongy, and look for skill books hidden around the island to expand your moveset and reach.
Bombs destroy boulders and cracked walls, and they’re also useful in combat. You can hit bombs with your hockey stick to launch them across the room. When you first get bombs, immediately think about everywhere you’ve seen breakable rocks throughout the island.
The Fire Plant shoots fireballs and is one of the most versatile tools in the game. Fire spreads to anything burnable nearby, creating chain reaction puzzles where you need to race burning bushes to trigger a distant switch. It also lights dark passages and is the weakness of certain enemies like toxic slime plants.
The shovel lets you dig up suspicious ground, and sometimes this leads to entire hidden caves and secret dungeons. It’s also used for nonogram/picross-style puzzles and is required to access the Cursed Chicken Coop area.
The Small Treat Bag is arguably the most creative tool in your arsenal. Use treats to lure animals like dogs, yaks, rams, and sheep onto pressure plates.
Guide rams to charge into obstacles and sealed doors. Give treats to mice hidden inside dungeons for extra hearts. You can even launch treats with your hockey stick to reach distant spots. Give treats to wild dogs and they’ll become your companion.
Give treats to wolves and they’ll join you as a computer-controlled party member that fights alongside you.
The Hiku bird is saved at the Lighthouse as part of the main story. It activates distant switches, retrieves hard-to-reach collectibles, and can also be used for fishing.
If you see anything suspicious that you can’t reach, try sending the bird to it.
A sign by the lake near town and a Master NPC in the woods will clue you into the fishing mechanic and reward you for catching every type of fish.
The Animal Karma System
Under the Island has an animal karma system, which means how you treat the wildlife on Seashell Island actually matters.
This is easy to miss if you’re not paying attention, but it affects your experience throughout the game.
Giving treats to animals and helping them builds positive karma. Being cruel or aggressive toward animals will have the opposite effect.
So resist the urge to attack every creature you see, especially if it’s not actively hostile toward you.
One thing to be aware of is that dog companions can be killed by monsters.
If an enemy hits your dog, it yelps and disappears.
There’s definite emotional damage involved. Keep this in mind when bringing your furry friend into dangerous areas, and consider leaving them behind before heading into tough combat zones.
Pay Attention to Your Surroundings
Under the Island hides secrets everywhere, but it almost always gives you visual clues if you’re looking carefully.
Training yourself to spot these environmental hints will dramatically improve your experience.
Different colored floors near walls usually mean there’s a hidden door or passage you can’t see. Walk into these walls to discover secret rooms.
Circles on the ground are often dig spots, so pull out your shovel and dig in the center.
Arrows in the terrain made from rocks, grass patterns, or other environmental features often point toward something important.
Slightly different patches of earth can be dug up with the shovel, sometimes revealing entire secret dungeons beneath your feet.
Bombable walls usually have subtle cracks. Cut grass, check behind trees, and investigate any spot that looks even slightly different from its surroundings.
The game rewards curiosity more than almost anything else.
Revisit Old Areas as You Progress
This is one of the most important habits you can build in Under the Island.
As you unlock new tools, previously inaccessible paths across the entire island open up. Every new ability is essentially a key to a dozen locked doors you’ve already walked past.
Koala Village changes as you progress through the story. Revisit regularly because NPCs will have new dialogue, new events will trigger, and new items or quests can appear that weren’t there before.
The Lumber Camp is especially worth revisiting because the workers gradually cut down trees over time. As those trees disappear, they reveal secrets and new areas that were completely hidden earlier in the game. Check back periodically and you’ll be surprised by what opens up.
Every time you get a new tool, do a sweep of areas you’ve already visited.
The game is built around this “tool sweep” approach, and it’s where some of the most satisfying discoveries happen.
Keep in mind that rocks you blow up with bombs stay destroyed permanently, but pushed blocks will reset when you leave a room.
Combat Tips and Staying Alive
Under the Island’s combat looks cozy until it suddenly isn’t.
There’s no dodge roll or shield, so positioning and spacing are everything.
Treat fights like a rhythm game: let enemies commit to their attack, step in, swing your three-hit combo, then step back out.
Some enemies require specific approaches.
Wolves pop out of the ground and can be tricked into surfacing underneath a bomb.
Toxic slime-belching plants are difficult to approach but vulnerable to a well-placed fireball.
Get creative with your tools during combat because the game rewards it.
Flying enemies in certain areas are a significant difficulty spike.
If they’re shredding your health, that’s the game telling you to leave and come back after upgrading.
Don’t be afraid to sprint past enemies when you don’t need resources. You don’t have to fight everything.
Here’s a huge tip that the game doesn’t tell you: enemies stay dead until you quit the game and restart. Even if you die, killed enemies remain gone.
This means you can brute force your way through tough areas by killing one or two enemies at a time, dying, respawning, and coming back to push further.
The enemies you already defeated won’t be there anymore.
Heart Coins, Upgrades, and What to Prioritize
Nia starts with three hearts of health. Every four Heart Coins you collect can be traded in for one additional heart added to your health bar. There are at least 38 Heart Coins scattered across the island, which is more than you technically need to max out.
Heart Coins are hidden everywhere: chests, buried spots, behind rocks, tree stumps, lockers, inside caves, behind puzzles, and even from the Monkey Fruit Party arcade machine if you score 10,000 points.
Cash them in as soon as you have four. Don’t hoard them.
Offering treats to mice hidden inside dungeons also gives you extra hearts, so always keep an eye out for them.
Honey is a key upgrade material found around the world that you’ll need for hockey stick improvements.
The Mystic Bear Ranar in Koala Village handles tool upgrades for damage, healing, treasure detection, and more.
For upgrade priority, focus on survivability first with Heart Coins and healing upgrades.
Then prioritize exploration tools that open new routes. After that, boost your hockey stick damage when enemies start taking too long to kill.
Save treasure detection and convenience upgrades for last.
Do the Mail Delivery Quest Early
This is a tip that can seriously impact your whole playthrough if you follow it.
Pick up the mail delivery quest as soon as it becomes available and stay on top of it throughout the game.
The quest has you delivering letters to various people around the island.
After you deliver one, pick up the next letter right away.
The beautiful thing is that you’ll naturally encounter the recipients as you explore, so it doesn’t require going out of your way.
When you complete the full chain of deliveries, you receive a very important item that helps you find secrets and figure out puzzles.
It’s one of those rewards that makes everything else in the game easier, so the sooner you finish it, the more value you get from it.
Puzzle Tips Including Nonograms and Timed Rooms
For nonogram puzzles, start with the biggest numbers in each row and column since they’re the easiest to place.
Look for lines where the clue total nearly fills the entire row, and use elimination to mark definite blanks.
The Cursed Chicken Coop has a whole chain of these puzzles that requires the shovel to access. Completing them rewards you with the Wonder Magnet. If you need help with the solutions, check out our Under the Island Nonogram Puzzle Solutions guide.
For timed rooms, take one slow practice lap first to identify the correct order of operations.
Find the action that permanently changes the room layout, then tackle the speed portion. If you keep failing, it’s almost always an order problem, not a speed problem.
Environmental chain puzzles use the Fire Plant’s spreading fire mechanic, where flames jump to nearby burnable objects.
Block-pushing puzzles unlock fast travel points and are always worth solving immediately. For animal puzzles, use treats to position creatures on switches and guide rams into obstacles.
The golden rule for all puzzles: if it feels physically impossible, you’re almost certainly missing a tool. Leave and come back later with new equipment.
Boss Fights Are Not What You Expect
Bosses in Under the Island are NOT just bigger enemies with more health. Each one introduces a completely unique mechanic or concept, and that’s part of what makes this game special.
Some aren’t traditional fights at all.
One boss involves managing lighting for a stage production and fending off fans trying to storm the stage.
Another is an Overcooked-style cooking competition.
The developers clearly had fun with these encounters, and they’re easily some of the game’s best moments.
You need to figure out the correct method to damage each boss.
Brute forcing with the hockey stick usually isn’t the answer.
Combine your tools mid-fight because bombs, fireballs, the Hiku bird, and treats can all play a role.
If you can’t figure out how to deal damage, look for environmental elements, interactive objects, or NPC prompts in the arena.
Always upgrade and heal before entering a boss dungeon. That marginal improvement is way more valuable when you’re learning new mechanics.
Collectibles and Secrets Worth Chasing
There are 18 Music Cassette Tapes hidden around the island.
Talk to Jon in the graveyard at night to get the cassette recorder, then start hunting. Tapes are scattered across every region and some are in tricky spots.
6 Volarian Murals are hidden in caves and secret areas, connected to the lore about the ancient Volarian civilization that built beneath the island.
The Monster Book fills out as you encounter every enemy type, and the museum/trophy room treehouse in the village tracks your achievements and clues you in about what you’ve missed.
The Mysterious Egg is found in a cave at the Harbour and requires both bombs and the Fire Plant to access.
Pick it up and it follows you around. After about 30 minutes of gameplay, it hatches into the Key-Rex, earning you the “#1 Mum” achievement and give you a key to access some of the island’s secret areas.
There’s also a hidden Developer’s Room somewhere on the island for the truly dedicated secret hunter.
For fishing, use the Hiku bird at any fishing spot. A Master NPC in the first screen of the woods will reward you for catching one of every fish type.
Minigames and Side Content
Monkey Fruit Party is an arcade game found on machines around the island where you catch falling fruit. Scoring 10,000 points earns a Heart Coin, scoring 15,000 points earns a honey pot.
Coconut Golf challenges you to get a hole-in-two for the “Golf ala Monkey” achievement and heart coin.
The Cook-Off is a cooking competition minigame where one round is mandatory for story progression, but you can replay it for additional rewards.
Snowboarding is a downhill racing minigame with a timed achievement, and the developers have patched the timer to be more forgiving than at launch.
You can also pet all the island cats and dogs. Because of course you can.
Save System and Common Mistakes to Avoid
Save at statues regularly. This cannot be stressed enough.
Under the Island uses a manual save system, and if you die without saving, you lose ALL progress since your last statue save.
This is the number one frustration new players report, and it’s completely avoidable.
Here’s a quick rundown of the most common beginner mistakes to watch out for.
Not turning on map location names leads to wandering in circles. Ignoring Heart Coins keeps you fragile way longer than necessary.
Forcing tough regions early causes repeated deaths when the real solution is to leave and come back with upgrades.
Forgetting to revisit previous areas as you progress means missing content that only appears later.
Not doing the mail delivery quest early means missing out on a tool that makes the whole game easier.
And underestimating animal treats as a gimmick instead of a core mechanic will leave you stuck on puzzles that have simple solutions.
The devs have been actively patching the game since launch, fixing progression-blocking bugs and quality-of-life issues. Keep your game updated for the smoothest experience.
Final Thoughts
Under the Island rewards the curious explorer who checks every corner, treats blocked paths as a to-do list for later, and revisits old areas with fresh tools. It’s a game that gets better the more you poke at it.
If you take away three things from this guide, make it these: turn on map location names, save at statues constantly, and use those animal treats on everything.
Do that, and you’ll have a much smoother and way more enjoyable time on Seashell Island.
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Images in this post are from the Under the Island page on Steam and used under Fair Use.