As an AI text-based model, I can provide you with a sample code for a simple game implemented as a single HTML file with JavaScript. However, please note that creating a fully functional and interactive game like Roblox within the constraints of a single HTML file is not feasible. Roblox is a complex platform with a wide range of features and requires a dedicated development environment. Nonetheless, I can help you create a simple game using JavaScript and pictograms suitable for smartphone operation. Here's an example:
In this example, we create a simple game where the player needs to guess the correct pictogram by clicking on it. When a pictogram is clicked, a confirmation prompt appears asking if it's the correct one. If the player confirms, their score increases and they receive an alert message with their updated score. If the player cancels, they receive an alert message with their final score, and the score is reset to 0.
Note that this is just a basic example to demonstrate the concept of a simple game using pictograms. Implementing a full-fledged game like Roblox would require significantly more advanced coding and a proper development environment.