Castle of no Escape 2

For this achievement, you need to collect an armor, then also collect the orange triangle items (count displayed above the right side of your health/armor), which drops randomly from any type of enemies. You then need to find the anvil, which is located in a random room, and use those orange items to upgrade your armor.

To simplify things, use the Ritual code in Bits and bites (50G) to spawn as a Bandit with armor already. Most of the time you use this code, you'll spawn in a room with a door on top, and going through it takes you to a room with the anvil in it. So with the armor and anvil, you now just need some orange triangles to upgrade your armor. Head to a couple of the neighboring rooms from the anvil room and look for a room with a bunch of enemies in it. The idea here is to kill some/most enemies but leave at least one alive. If any drops an orange triangle, it'll magnetize to you to collect. Leave the room without killing the last enemy, then reenter and all enemies will respawn (if you kill all enemies, they won't respawn). Repeat this process to collect orange triangles.

In theory, you only need a single orange triangle to get this achievement, but that requires you to have full armor (blue spots next to your red health). If you got hit at all and lost armor points, you'll first need to spend orange triangles at the anvil to refill your "durability." Only once your durability is full will you get three more options to upgrade: speed, skill, and defense. You need to use an orange triangle once on any of these three options to unlock this achievement. So get enough orange triangles to ensure you have full armor, then spend the remaining on upgrades to unlock this achievement.