Chasm
20 Achievements
20-25h
Explorer
Explore 100% of the map.
7.3%
How to unlock the Explorer achievement in Chasm - Definitive Guide
On the map screen you will get a green check mark next to the name of the area when you have it full explored.
The interior rooms inside the inn count (I popped the achievement upon visiting the professor’s room)
Hidden rooms and passageways don’t count.
Some areas in the magma chamber map can only be revealed by sinking into the lava.
Don’t worry to much about backtracking early, most rooms don’t contain anything overly useful and some require multiple pieces of gear to fully explore. Wait until you unlock all the traversal gear and save yourself from repeated backtracking.
*My first playthrough glitched and wouldn’t give me the achievement, the end screen credited me with 100% but didn’t unlock. Just be aware that this is a possibility.
For those wondering, YES YOU CAN CONTINUE YOUR GAME after beating it to get whatever rooms you missed. Look for the area maps with the green check mark and then look around for any uncovered map part or door that you didn't enter.
You need to uncover every part of the map for this trophy to unlock. Some rooms are big and you will need an artifact to jump up the walls/reach far distances before that section of the map is uncovered. This trophy was testing my patience and I was close to believing it was glitched, but it’s not. Look carefully at each map for little gaps in the borders; this means there is a door there you haven’t gone through yet. Check all large rooms to make sure that each square on the map is uncovered for that room. Some artifacts are needed to uncover parts of the map.
There are little secret rooms in some areas accessed via hidden walls...these are not part of the map. Also, you do not need to open every chest/break all boxes for the map to be considered 100%. Credit to Marty84 for mentioning this.
See Tips by Timmah200. You have to uncover the entire map on one save file. The Outpost at the beginning of the game is already uncovered for you.
Areas Most Commonly Missed:
Titan Boss Room in the Gardens (jump up the walls on each side).
Lock puzzle in the Catacombs (jump all over to uncover that last square).
Double-jump ledge in the Keep (right after you parachute over to continue with the level…you need the Winged Boots).