In Daemon X Machina, Femto particles power your Arsenal suit to all kinds of new heights. Femto is an external resource that came about when the moon cracked. It has since changed the world in many ways.
When you destroy enemies, they drop Femto which you can then pick up by flying through it. There are also specific areas of the map that contain Femto crystals that you can absorpt Femto from if you stand near them.
How The Femto System Works
If you push down on the right thumbstick, you create a Femto clone of yourself to distract enemies while you reposition. You can then push down on the right thumbstick again to end the clone.
Pushing up or down on the D-pad activates three different Femto systems that increase your damage output, ability to take damage, or your thruster speed. You can quickly cycle through them to activate the ones you want, although when you use any of them fully, it goes on cooldown.
If you carefully watch your Arsenal, it is easy to see which one is active. Circular cones of red energy around your arms indicate increase damage output. A full circle of small red cells around your Arsenal indicate increased shielding while glowing red particles around your thrusters indicate increased thruster speed.
In your HUD, there is a row of circular symbols. The last three on the right denote each of the abilities, how much charge each one has left. When they are on cooldown, they are grey.
The trick is to ensure you are collecting as much Femto as possible to keep your abilities powered up, then cycling through them as you need them.