Debugging Fast-Paced Action Games

"During the development of my last game I took a different approach of debugging it which is especially useful for real time games. Because it's so simple I'm wondering why I haven't used this method before (perhaps too lazy ? ;-)) Usually you include a bunch of trace statements everywhere or create a logger system which prints out the information you need. But this is useless in games where many simultaneous events occur. Your logger will be flooded with messages so it's hard to keep track of everything."