Non-gamer me did fine on the default mode (medium), so if you're a real gamer you'll probably want hard/insane mode. Playing in easy mode allowed me to win, which should tell you how easy 'easy' is. (I'm not fast at hitting buttons and I tend to hit the wrong ones over and over, yet I still could win, yay!)
Yay dinosaurs! Yay fire raining down from the sky!