I really enjoyed this.
I can definitely feel the Undertale influence here as well as Pokemon Gen 1 for the visuals.
The battle plays out like a little puzzle and it made me laugh a couple of times. Humor can be very subjective but this is just the right amount of silly to make LOTS of people laugh I feel.
Story based games face the challenge of integrating gameplay early enough and it's good you have the player do something pretty much right out of the gate since the interactivity is what makes you invested in the story.
Here's a couple of things that could be improved on:
When choosing the boy or the girl let a default cursor show up on the screen, with one of them already selected. It only appears once you press left or right and I honestly thought my game game froze for a couple of seconds.
I think I know what you're going for with the .txt files included in the game, but honestly? Your storytelling is strong enough that you can do without them. Additionally, account for hostile users. Some players simply won't open those files or read instructions.
Is the window size a design choice? I usually get grumpy when I can't resize the window, but I can see stuff popping up outside of it during the gameplay so I'm looking forward to seeing what else you got cooking here.
In conclusion: please keep working on this! I'll definitely play more when you release a new version.