Playing Serious Sam 3 recently and apart from technical issues trying to get it to run, it's an engaging game. I'm actually dying on a regular basis (after having gotten into the last half of the campaign). Which of course just takes you back to the nearest quick save - making it a puzzle shooter essentially. It's not really about massively good aiming skills with the mouse (like Quake live is). It's about figuring the right corner to hide in, the right weapon, or even right sequence of weapons to use. And about knowing when to run away!
Good to play a game which actually fights back against you/is cunning enough to kill you a few times.