Creatures

Take appropriate tile size

Consider 32x64 a default template for human-sized creatures:

Monster sprites should have ~8px offset from the ground

To give them a 3D look.

Facing to the right by default

And remember that tiles are mirrored when creatures move.

Monsters should drop shadows when possible

// TODO: add monster with a shadow image

Put shadows in a bg field in json, use shadow_<width>x<height>_<size> template. You can find shadow files in the root of any size directory (e.g. pngs_normal_32x32).