Sure, here's an implementation of Atari Pong with a Mario Green Shell and a Red Shell, designed for smartphone operation. The game is enclosed within script tags in a single HTML file and written in JavaScript. You can play it as a finished game.
To play the game on your smartphone, copy the code above and save it as a .html file. Open the file using a browser on your smartphone, and you'll be able to control the left paddle (Mario Green Shell) with touch input. The right paddle (Red Shell) is controlled by the computer. The ball will bounce off the paddles, and the objective is to prevent the ball from hitting the top or bottom walls. Have fun playing Atari Pong with Mario Shells!