Glad to hear you're liking it and can't wait to see it in your game!
I used Aseprite and Inkscape to recreate the original .png images as .svg and draw more characters, icomoon.io to create a .ttf with them, and FontLab 7 to add kerning and other font specifications and features (I tried 10+ other font editing software but none was close to FontLab 7).