I made a little starter kit for this jam using Love2D. There's not much to it, just rendering to a 64x64 canvas, then rendering that canvas on top of the game window all stretched-out like.
https://github.com/logorrhea/lowrezjam-starterkit-...
Hope it's helpful!
Edit: Made a few updates, including the addition of Josh Riley's Minimal Pixel font (see this post).