Puzzle hand-crafted by gradually adding clues until a unique solution. Both the puzzle and the image is created by me, Oceanh.
Credits:

The svg-diagram is a derivative work from Image:Hypersudoku400 Start.svg [1] created by User:Vystrix Nexoth (and uploaded to the English Wikipedia under the GNU Free Documentation Licence), from which a significant part of the svg-code for colors and line drawing is taken. The design of the diagram is further a derivative work from Image:Hypersudoku400 Start.jpg [2] created by Chris McCusker (and uploaded to the English Wikipedia under the GNU Free Documentation Licence).
No machine-readable source provided. Own work assumed (based on copyright claims).
No machine-readable author provided. Oceanh assumed (based on copyright claims).