Sure, here's an example of a single HTML file that implements a simple fantasy RPG game similar to Pokemon. The game will utilize pictograms and can be played on a smartphone:
Fantasy RPG Game
This HTML file sets up a game screen div where the game updates will be displayed. The JavaScript code includes the game logic for the player and enemy attacks, when to end the game, and updating the game screen with relevant information. It starts the game by displaying an initial encounter message and initiating the first attack between the player and the enemy.