For more, see concept art for Splatoon
Various concept designs of the School Uniform.
Examples of Inkling customization, with several early gear designs.
Several sub weapons.
The .52 Gal.
Elements of Camp Triggerfish.
Elements of Urchin Underpass.
Elements of Kelp Dome.
Elements from Octo Valley.
Early single-player stages.
For more, see concept art for Splatoon 2