mudSkipper

Controls

A / Z: place down tile or object
(hold) B / X + LEFT or RIGHT: swap between tiles 
(hold) B / X + UP or DOWN: swap between tile sets 
START / RETURN: open options menu
SELECT / SHIFT: open build menu
ARROWS: move cursor or navigate menus

!TO SAVE!
left click in your browser (Firefox, Chrome, Safari for sure work) and select "save image as"

Editors

EXT: made for rapid development, split into sections oriented to build a number of useful outdoor maps fast and intuitively.

INT: for rapid indoor map making.

SIDE: bonus editor for simple sidescrollers.

FREE: place each tile down one by one for total control over your design.

finally including a ROM since i feel like it's functional enough finally-- PLUS I added the raw project files for $5 in case anyone wants to tinker around in it and customize or expand on their own version.

more updates coming soon!