NPAPI is starting to be phased out which unity player depends on. However with the new Unity player 5.0 being based on WEBGL They moved to unity a while back it look like and are looking for feedback [https://www.kixeye.com/forum/discussion/489242] however since this was posted over a year ago, try to start the game in Safe Mode. What this will do is disable hardware acceleration. If you see an improvement you can disable. You might need to restart Firefox in order for this to take effect, so save all work first (e.g., mail you are composing, online documents you're editing, etc.). Then perform these steps: #Open Firefox ''Options'' window (''Preferences'' on Mac or Linux) as follows: #* In Firefox 29.0 and above, click the menu button [[Image:New Fx Menu]] and select ''Options'' for Windows or ''Preferences'' on Mac or Linux. #* In Firefox 28.0 and previous versions, click the orange Firefox button at the top left, then select the "Options" button, or, if there is no Firefox button at the top, go to Tools > Options. #In the Firefox Options (or Preferences) window, click the ''Advanced'' tab, then select ''General''. #In the settings list, you should find the ''Use hardware acceleration when available'' checkbox. Uncheck this checkbox. #Now, restart Firefox and see if the problems persist. Additionally, please check for updates for your graphics driver by following the steps mentioned in the following Knowledge base articles: * [[Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems]] * [[Upgrade your graphics drivers to use hardware acceleration and WebGL]] Did this fix your problems? Please report back to us! Thank you.