In order to use np2android you need three things:
All of them can be found in this archive.
To make games run smoothly do not forget to disable vsync and frame-limit in settings.
By default emulator provides software keyboard, but it is often desirable to use hardware keys with custom mappings. Current method is described in this blogpost (Japanese!). Short summary: keymap file should have extension .key and have format
Android scancode,PC-98 scancode
(see mentioned blogpost for meaning of PC-98 scancodes). List of Android scancodes can be found here. Example keymap file, replacing directional keys with WASD keys can be found in attachment.