Nice concept, but gameplay needs improvement.
The concept's quite original and fun to see it bouncing around dodging bullets while following the 'law of physics', but I think you need to add in more features to benefit the player.
A couple of things that I find :-
(1) It's pretty hard to get that extra life, especially when it's gliding down slowly while the next enemy gets in and starts shooting the player. Doesn't help when the extra life just drops off the ground level.
(2) Machine gun aiming is random while moving, making it extremely difficult to aim. I notice this especially when I'm at the same level or above the enemy ship.
(3) Manueverability of the ragdoll is clumsy thanks to the 'law of physics'. I find myself in tight spots most of the time, when the enemy shots are close with each other.
The lack of strategy and just mindless dodging while praying that the ragdoll's bullets actually hits is not appealing. You might want to consider features such as power-ups (e.g bouncing bullets) and tactical advantages (e.g. usage of terrain to dodge enemy attacks) to aid the player.