The sparks and wall-hits were taken from the Video Copilot - Action Essentials 2, its a pack of pre-keyed/ transparent action effects like explosion etc. for video editing, but you can import them into photoshop and pick out single frames.
In this one I used a concrete hit effect and colored it red for the blood splatter and added a bloodcloud and a bodywound, but normally I start with some splatter texture or brush, motionblur it a bit, add a small bodyhit and change the layermode around, and then i add a red cloud-brush on top. Also dodge and burn the clouds to get a deeper effect.
For the isolation process, i use the polygon lasso to select every single character/object i want to work with later and copy it over to its own individual layer for convenience. i also erase the objects from the background using content aware fill but thats just a preference of mine so i can liquify the edges of the characters and smooth out the models. Its pretty complex, I guess i should make a tutorial video sometime.