Customize your gear
In Splatoon 1, your gear pieces gained random new abilities as you leveled them up, and that was that. In the new version, though, you can take finer control over your gear stats by visiting Murch, the hip-looking urchin who hangs out to the right of the Lobby in Inkopolis Square.
You can have Murch scrub any of your gear pieces clean, which costs some serious cash but will earn you special ability chunks. These chunks can then be used to add and remove specific abilities to your gear piece of choice, allowing you to double down on things like speed, ink recovery or whatever else suits your playstyle.