Sure! Below is a simple implementation of the game you described using JavaScript, HTML, and pictograms. The game can be played on a smartphone, and the goal is to shoot all the watermelons. However, there's a twist - if you win the game, you'll become "fat" (represented by an arrow pointing to a bulging character). You can copy the code and save it as a single HTML file to play the game.
Please note that you need to replace `emozi_all/pictogram.png` in the code with a valid URL pointing to your desired pictogram for the "fat" state of the character.