If this video is your own work or a reference you are studying, a "solid essay" (whether video or written) typically features the following key elements:
Video Essays 101 - Digital Liberal Arts - Macalester College
While the specific video file appears to be a personal recording or a specific submission not publicly indexed as a viral "solid essay" example, the phrase often refers to high-quality Video Essays that combine narration with visual evidence to make a compelling argument.