SteamWorld Dig

(Missable)

There are 20 secrets total in this game. All the secret areas are found in caves inside the mine, usually tipped off by different-looking rocks/plates and most secrets can be found easily by obtaining the Mineral Locator in Vectron and backtracking through the caves. However, there are a couple secrets that are just out of range of the locator and will need to be searched more thoroughly for.

Or, you can follow more detailed information in this helpful steam guide by Ralf, and in the spoiler box below: https://steamcommunity.com/sharedfil.../?id=314966329

Area 1: Archaea

This secret is located in the generator room. As you enter the room, walk to your right and the secret will be right beneath your feet.

Secret 2: Cave 1

Further down the generator room, when you need to break the dirt for the little magnet to create a platform on the right side, head slightly more to the left and mine upwards. The secret will be here.

Secret 3: Cave 6

This is the cave where you get the drill, at the very bottom of Archaea. Enter it, jump past the trilobites on the left, then jump to the patch of dirt right above the entrance. The secret is inside.

Area 2: Old World

Secret 4: Cave 4

This secret is located in one of the optional caverns in the Old World. Enter the cave, jump down and kill the shiner, bounce your way through, then in the little corridor on the right, hit the patch of dirt for a secret.

Secret 5: Cave 5

With the Static Dash, this secret is very easy to get. Jump up all the way, then walk to the right until you see a sleeping shiner. The secret is a patch of dirt to the left of the guy. Without the static dash, you'll need to go all the way around. To the left, down the ladder, past the acid, up the ladders, past the acid again, kill the bottle-throwing shiner with TNT, then jump up the wall above him and head towards the sleeping shiner.

Secret 6: Cave 6

This one is very easy. Just walk towards the left and hit the wall.

Secret 7: Cave 6

Take the bouncy mushrooms to your right and jump all the way up until you see a large orb stuck in dirt in an inaccessible area. The lantern isn't bright enough to fully light up the secret tile, but it's visible in the screenshot. Just break that block and you're good to go.

Secret 8: Cave 6

In the room where you get the fall dampeners, there's a patch of dirt in the left wall. You'll need the steam punch for this, as ladders can't be used in caves. As per the other secrets, break it open and the secret is yours.

Secret 9: Cave 5

The final secret in the Old World is in the generator room in cave 5. Once inside, head left, then go up to the crates placed over an acid pool. You need to leave one crate on the platform in order to access the secret, do so via dynamite on the top crate, or step on a gap in the crates, punch the one above you, then take out the crate you were standing on. That's it for the old world!

Area 3: Vectron

Secret 10: Cave 2

From the entrance, head left, jump up to the maze and head right. The secret is in front of you.

Secret 11: Cave 2

Once you get the mineral detector from the room specified in the screenshot above, hop on up to the top right platform and hit the right wall with one or two fully charged steam punches. The secret message should appear.

Secret 12: Cave 2

You won't be able to get this secret without destroying the generator first. Once that's done, jump up to the top corridor and punch a hole in the ceiling.

Secret 13: Cave 4

Again, the generator must be destroyed before attempting this secret. Go back to the turrets when that's done and break the left wall. The road to the actual ore is very far, so this secret is easily missable.

Secret 14: Cave 4

Right after jumping past the lasers in this cave, jump down, step a few tiles to the right, and punch upwards. You'll get this secret.

Secret 15: Cave 4

Right from the generator room, you'll see a pool of water in a wall, along with some ore. Hit the block to the right of that ore.

Secret 16: Cave 4

Once you've destroyed the generator, hop back down to the platform you steam jumped from, and use steam punch on the wall to your left. This is another easily missable secret.

Secret 17: Cave 5

This one's easy. It's under the lower laserbox, to the right.

Secret 18: Cave 6

Try not to die as you dodge the crazed exploders in the room. The secret is beneath you once you've passed them.

Secret 19: Final Cave

The final secret you'll get before you face the antagonist of the story. You can sprint past the laserboxers at the beginning, but you will get hit, so just deactivate them temporarily. The block you need to destroy is just past your lazers.

And there you have it! Enjoy your new, shiny trophy.