I built a simple HTML/JS single-layer map utility so I don't have to manually create the map arrays for the game.
It allows you to customize the map size (specifying dimensions in a mix of screens or tiles), load a custom tileset and choose a light or dark background color. Oh and create a map of course.
Still to do, open existing maps and save your creations (probably via a textarea that you will paste/copy a C style array to/from) and support for multiple layer depths.
keyboard shortcuts: ← previous shot → next shot L or F like Z toggle zoom