This game is fun for the exact opposite reason that Metal Gear Solid is fun.  In this game stealth isn't of much importance, while quickly killing all the bad guys on the screen is important.  Like most action games this one is staged out into many different missions, which usually have five or six objectives in order throughout the level. My personal favorite aspect of this game is the target system which locks on to the enemy of your choice making the game easier in a crowded room of enemies.  Syphon Filter is one great pure action game.