Here is an example of a playable game implemented as a single HTML file using JavaScript:
In this game, you will be prompted to visit different websites (YouTube, Twitter, Discord, Instagram, and Snapchat) and find the specific letter indicated in the clue within a numbered list on each website. The letters are associated with specific numbers (O: 4, E: 5, P: 2, N: 1, R: 3). You need to input the correct number code for each letter to proceed to the next clue. Once you have successfully found all the clues and entered the correct codes, you will be congratulated for finding the word "Prone".