A NES Sprite [CHR DATA] editor.
You can use it here: xeinherjar.github.io/nixel
This is my Capstone Project at The Iron Yard Atlanta.
Nixel allows you load a Nintendo ROM file and edit the sprite data contained within. You may edit roms with CHR data (most games) or games that load their sprites from PRG data (Zelda, Metroid, Mega Man).
After you make changes you may then patch the ROM and play with your new graphics.
Due to how palettes are stored/accessed/used Nixel is not able to edit them.
ROMs are not uploaded to a server for these changes, they all happen locally in the browser.
The title font can be found at http://www.iamcal.com/misc/fonts/