Yeah, you can play with a regular controller, 3D controller, or even the Saturn mouse apparently. But obviously it is more fun with a lightgun, at least for the shooting parts. The regular visual novel parts aren't too great with a gun though.
Lightguns do not work on any TV that isn't using CRT technology due to the way they are designed. You can emulate them thankfully with IR sensors, such as in a Wii remote. You can also buy lightguns custom made, or make one yourself with online diagrams. Sinden and Gun4IR are the two most popular, but there is another one that has a strange German name I am drawing a blank on that uses Wii remotes as well.