Your story effectively creates a suspenseful atmosphere, blending elements of the supernatural with the mundane curiosity of modern ghost-hunting technology. The setting, a well-maintained but abandoned house, serves as a perfect backdrop for protagonist's exploration. The use of a ghost-hunting app as a narrative device adds a contemporary twist to the traditional ghost story, providing a unique way for the protagonist to interact with the unknown. The tension builds nicely throughout the narrative, culminating in the chilling single-word message, "RUN," which leaves the reader on edge.

While the suspense is well-developed, I think the story could benefit from deeper character development. Learning more about Angela's motivations for exploring the house and her previous experiences with the supernatural could enhance the reader's connection to her. Additionally, some elements introduced in the story, such as the mention of the track team coach, feel to me as if they're a bit disconnected from the main narrative. Tightening these loose ends or integrating them more fully into the story could improve overall coherence and impact.

This narrative is engaging and well-crafted, with a strong sense of mood and setting that pulls the reader into the mystery. The modern twist of using a ghost-hunting app brings a fresh perspective to the ghost story genre. By deepening character backstory and ensuring all narrative elements are tightly woven into the main plot, the story could offer even more depth and satisfaction. Nice work!