You can always play the newest version here. When asked for permission to run / install plugin, proceed as requested by Unity Player.

However, please note that due to the internet connection limits, the quality settings are automatically set to the lowest possible. The full version of the game looks much cooler and is more user-friendly. To fully enjoy the game & graphics, download the game to your computer.

Also, because of the applet limitations, you cannot submit your highscore when playing online.

Unity Web Player | Power Defender