While Wind in the Willows features only one actor, the story is also told with the help of multi-media elements, like 180-degree projections, music, and soundscapes. It’s all an example of multimedia theatre, which refers to theatrical performances that incorporate various media, like audio, interactive technology, lighting, and video.

Multi-media theatre may be divided into two types, based upon the potential for audience interaction: Linear multimedia does not react to performances themselves; instead, its changes are controlled by technicians operating under the direction of stage managers. However, interactive multimedia is responsive to the actual performers and other elements; for example, these multimedia elements may be triggered by the physical movements or voices of the performers.¹

Regardless of what multimedia elements a production might use, the goal of its use is to further affect an audience:

Phantasmagoria

The most prevalent use of the magic lantern used in performing theatre was with phantasmagoria, a type of performance wherein projected images--amongst other tools--were used to frighten people. Such performances originated with fraudulent séances in the late 1700s, and, often, phantasmagoria audiences were under the impression that the imagery they were seeing was real.

Around the time of the late 1700s, Étienne-Gaspard "Robertson" Robert was the most popular creator of phantasmagoria. One of the refinements to the magic lantern that made his shows so popular was to attach wheels to the device, so that he could easily create the appearance of moving images, as well as images that could easily grow and shrink in size.

In a testament to his skill as a showman, his art was once stopped by police who were acting upon the belief that he had the supernatural ability to resurrect Louis XVI.⁴

(The above image is a depiction of one of Robert's phantasmagorias.) 

1. https://worldoftheatreandart.com/multimedia-modern-theatre/#:~:text=MULTIMEDIA%2C%20Meaning%20and%20Possibilities,space%20elements%20and%20their%20function. 
2.  https://www.numberanalytics.com/blog/multimedia-performance-in-theatre 

1. https://www.britannica.com/art/periaktos 
2. https://ancienttheatrearchive.com/glossary-term/periaktoi-%cf%80%ce%b5%cf%81%ce%af%ce%b1%ce%ba%cf%84%ce%bf%ce%b9/ 
3. https://commons.wikimedia.org/wiki/File:Visual_reinforcement_magic_lantern.jpg 
4. https://en.wikipedia.org/wiki/Phantasmagoria