General Layout

The above image is a little confusing, so I'll break things down.
Section 1: Isaac Episodes

This is what you're probably here for. All runs and gameplay events are saved in those 4 tables!
An episode can be broken down into a series of one-to-many relationships:
- An episode consists of multiple played characters
- A character went through multiple floors
- A floor had multiple gamplay events.
The corresponding tables:
video_submissions
all isaac episodesplayed_characters
the characters that were played in those submitted episodesplayed_floors
the floors the characters went throughgameplay_events
the events that happened on those floors
The tables also reference themselves in that direction, meaning...
- everything that belongs to a submission references
video_submissions.id
- everything that happened to a character references
played_characters.id
- everything that happened on a floor references the
played_floors.id
Section 2: Game Resources

All game resources are stored in "isaac_resources". Be it pills, items, transformations, floors, characters, enemies... everything. The only thing that keeps them apart is the "type" column.
"mods" and "mod_url" store mods from which "isaac_resources" came, as well as hyperlinks to those (for example a link to the steam workshop page)
If collecting an "isaac_resource" counts as transformation progress, then that property is saved in the "transformative_resources" table.
Section 3: Video Data

"videos" saves youtube-video related stuff like upload date, video duration and so on. Most of this stuff is directly pulled from youtube. The "thumbnails" table is self-explanatory.
"quotes" are the funny quotes that users submitted while watching.
"discussion_topics" are tangents and broad themes NL talked about during an episode.
Next Step
A detailed table description and query examples