The Latvian Gambit is an incredibly aggressive opening type of defense for black against one of the usual openings for white to e4. At masters level, this opening is not used much because most masters decline to give away pieces early in the game.
In the video, Kevin described the Latvian Gambit in general as an all-out-war doing whatever it takes in order to checkmate your opponent, even though that means sacrificing a few pieces. There are strong enthusiasts of the Latvian Gambit below master level game play, and Kevin points out the possibilities may arise that will lead you to high probability of an easy win.
The Latvian Gambit is an exciting opening because white doesn't have many good choices besides waiting for the gambit. When white resists the gambit, black can have the benefit of an identical aggressive tact with this f-file open, possibility for a castle rook, and black will not be down in material. It is the reason it is much more typical for white to accept the gambit with Nxe5. From this point, black has other aggressive options to take and go for the win. It is suggested that when playing this opening, you should avoid focusing on taking down one pawn immaterial and claw back the rest of the game.
Check this Latvian Gambit video. Learn it and use it against your opponents. They won't see it coming!