A good mediocre shooting game
This could be called a Korean horror version of Touhou, and that's pretty much what Shikhondo is.
While the game's shortness is not a problem as a shooting game shouldn't overstay its welcome, numerous points in design fail. While production and visual design are good, each of the boss use lower resolution sprite for the zoom effect, which looks extremely bad with all the pixelation you get with it. Some other elements suffer from this as well, but not nearly to the same extent.
Music is nice to listen, but nothing memorable. It's pretty much inoffensive elevator music. That's pretty much par for the course, sadly.
Shikhondo is like so many first time entries in a series; it's janky, lacking in content and design, many of the visual choices are lacking and play balance can be whacked in places. It's an enjoyable little game, but not exactly stellar game of the year material.