The Google Chrome browser comes preloaded with a version of Adobe Flash, which is named “PepperFlash.” Unfortunately, some browser-based applications, including Tetris Battle, don't always play well with this plugin. Fortunately, you can easily disable the plugin, and then add a new version provided directly by Adobe.
To disable PepperFlash:
1. Open the Google Chrome Plugins page by typing this URL into the address bar: chrome://plugins
2. Locate the "[+] Details" button in the upper-right corner of the Chrome Plugins page to display additional details for each installed plugin.
3. Scroll down the list of plugins until you locate the "Flash" plugin. Note, there may be several plugins for Flash already installed. The first plugin listed in the Flash section is the PepperFlash version.
If the Flash section only has one plugin listed, be sure to visit the Adobe website first, and then download and install the Adobe Flash Plugin for non-Internet Explorer browsers.
4. Once the new version of Adobe Flash has been installed, you can click on the "Disable" link associated with the PepperFlash plugin to turn it off.
Note, please be sure the alternate version of Adobe Flash you have installed (see Step 3) is enabled before disabling PepperFlash.
5. Close the Google Chrome browser, and then restart it.
Now try playing Tetris Battle again, and hopefully you'll see a noticeable improvement in the overall performance of the application.