Experience

Experience is a stat of a weapon that usually determines how strong is the weapon. In the case of the Nemesis, leveling up actually greatly decreases its overall performance. The Blade's throwing distance at Level 2 is slightly shorter than it is at Level 1, but it is more powerful. As for the Spur, the "shoot button" must be held down to charge it to level up, and energy crystals just make it charge faster.
Unlike most games, the player loses experience if they take damage, and experience does not carry over from weapon to weapon. All weapons have 3 levels. The experience bar of each weapon is the yellow bar atop the health bar in the top-left corner of the screen. Next to the bar is the current weapon's level. If a bar gets completely full it moves onto the next level, and after filling level 3's gauge, added experience allows an extra bar to be filled, showing the word "MAX" on the bar. This does not level up the weapon, but it acts as a buffer to prevent being reduced to level 2 on the first hit. Similarly, a weapon's experience depletes until it reaches level 1 with no experience. If Quote obtained Arms Barrier, the experience loss when damage is taken is halved.