Sure! Here's an example implementation of a mobile-friendly game inspired by Undertale that allows you to customize your character. Keep in mind that due to the limitations of text-based format, it may not fully represent the game experience but should provide a starting point for your own implementation:
Undertale-inspired Character Customization
Your Character:
To try out the game, copy the entire code and save it as an HTML file (e.g., `undertale.html`). Then, open the file with a web browser on your smartphone. You'll be able to customize your character's color, expression, and weapon before starting the game.
Note: The code provided is a simplified example and an actual mobile game implementation would require more complex logic, visuals, and gameplay mechanics.