I'm black in this one. Komi: 6.5 points.
Slow steady development in the middle game resulting in black being in the lead by over 15 points.
Here, the lead was about 10-15 points.
Here's the beginning of the game of chess between myself and Miro, @gamer00's younger son.
I know next to nothing about opening theory but I felt developing the knights before the pawns was not a good idea. The game involved trading a lot of the major pieces. I made sure to trade the knights first because I thought bishops were more valuable when the board is emptier. I had a small material advantage until I lost one of my knights without gaining anything. Through a slow grind I gained a material advantage having three pawns and a rook against just one knight (and the kings) in the end. I checkmated the opponent when he was trying to keep from one of my pawns becoming a queen.
I once who played my wife's nephews, 8 and 9, who had played in a chess club and who had been taught before and won a similar game where they consulted each other. But I have no idea what my chess skill level is in terms of an ELO rating. In middle school, I used to play chess regularly with a classmate of mine after school for a few months, if I recall correctly.
I got curious. Perhaps I should make an account on a chess server and try. I'm probably no match for a real player who has been spending any time trying to improve. Miro told us 800 is the initial Elo rating of a player but he gave no clear answer as to whether there is a lower limit.
[Edit: My strength is about equal to the bot on lichess.org playing at Stockfish 3 level. According to multiple sources, that would put my Elo-rating in the range of 1100-1400.]