It's very challenging. In a normal writing process, you have the luxury of time to plan, research, and rewrite. But with a '24 hours novel', you have to dive right in. You might not have enough time to fully develop complex characters or intricate plots. There's also the fatigue factor as writing for 24 hours straight can be mentally and physically exhausting, which can also affect the quality of the writing.
Writing a '24 hours novel' is no easy feat. You not only have to be creative but also highly organized. First, you need to quickly decide on a story idea. Then you have to flesh out characters and build a plot structure. And all this while making sure your writing is grammatically correct and engaging. The lack of time means you can't afford to get writer's block or waste time on unproductive ideas.