I recommend starting of with the beginner tutorials: https://www.scirra.com/tutorials/253/ho ... tform-game
. That one covers all the basics of a platform game. The shooting wouldn't be too hard, all you have to do is to make a sprite for the hand, add the Pin behaviour to it and rotate it towards the mouse every tick. When you left click you have to create a bullet and there is also a behaviour for that, too. I haven't worked much with physics, but I believe if you wanted ragdoll physics you'd have to create your enemies out of multiple sprites(head, body, hands, legs) connected with the revolute joints. However making them like this makes it hard for them to walk normally while alive. You could also have a normal sprite for when the enemy is alive, and when he dies create the ragdoll object(multiple sprites as I mentioned before).