The Bug Princess is finally widely available in the USA. Mushihimesama is one of Cave's most beautiful shooters and the culmination of a decade in developing the craft that is a modern shooter. Significant level of detail is given to enemy placement and movement, as well as bullet speed and patterns.
Quality Cave shooters are more like a well choreographed dances and Mushihimesama is maybe the pinnacle of Cave's efforts without relying heavily on fan service or tropes. The artwork and character sprites are absolutely gorgeous. The game comes with many options, monitor rotations, an arranged mode, and a 1.5 update.