The "Your Sword Is Enough" achievement requires you to beat the game without ever obtaining the Smart Gun.

Although it's not possible to beat the game without the use of color magic, there IS more than one way to use color magic, and that would be by using the Sword Wave ability.

Sword Wave is located in Durridin Forest inside a room walled off by a handful of blue blocks.

Normally you're supposed to come back after you obtain Blue magic in Ryha River, but there is another, probably ALSO dev-intended way of entering.

Simply get to the area where this level's special coin is located, and instead of turning around, jump forwards off of the platform.



You will land on this tree, where you can continue walking forward until you reach the room from below, afterwards you can then jump up and into the room where Sword Wave is held.



Sword Wave comes prepacked with Red magic, which you can use for free.

After leaving the room, you'll be placed just outside of the blue blocks,