I want to thank everyone involved in the development of all the great tools that made this project possible. The project is developed on a Linux machine (Ubuntu Gnome 15.04) with the following tools:
Not a tool but a really cool HTML5 game framework that the project is based on. A modified version of Phaser Virtual Joystick plugin is used for touch controls.
Gimp and Export layers plugin
The plugin allow you to export all layers as separate images witch is perfect for making an animation with a frame per layer. Just extract into a texture packer smart folder.
Really great tool to pack all your sprites. Efficient, quick and easy.
Metroid specific rom-hacking. Makes it possible to dump all Metroid map as image, which I then use the scripts described above to convert to a tilesheet and tilemap.
A free hackable editor that just gets better.
The game is written in ES2015/ES6 transpiled and package using this Phaser ES6 Boilerplate.