What a smug grandson. No wonder Oak was so proud that Red humbled him. I miss the fact that after gen 1 they stopped updating the trainer sprites themselves to showcase a difference in experience. Like at the start, Green's pompous, smug, often mentions you smell, but is always one step ahead of you. Even if the first two matches you have are ones you are allowed to lose, only in Yellow will it influence how he responds to you. Because he will either evolve his Eevee into Jolteon, if you won both matches, Flareon, if you won the first match but ignored or lost at the second, and Vapeoreon if you lost the first match and or ignored the second. His team's composition reflects that and it's fantastic. In a narrative sense, he is willing to go easy on you or give it his all because of how you performed in the first two significant battles. The layers to the very beginning of Pokémon are small but humble in how you eventually sort out the world. These days we don't really get that much since they aren't willing to experiment and bring about a challenge that connects to the narrative. I suppose in that respect that is what makes gen 1 so fascinating... both the glitches and the narrative at hand in how you choose to proceed after your losses and victories. I could go on but I don't want to burn out the character limits on a review like this.
Side note, it is a good detail to add the poster in the back that lets players know how to save. People take for granted just how important of a feature it is and to do so just about anywhere. Since back in those days making a consistent save point for the player was difficult to program. Heck, even the save chime is different in the first three games even if the pitch is only slightly altered.

What a brat! The first time we both got a Pokémon and already wants to sic his on me!