What kind of pump works for hard to reach kids valves? Could you recommend a pump that can inflate this?  I want to jump off a bridge right now :/
That looks like you need to push the valve in from the back (i.e. put your thumb on the tire side and push towards the rim so that the valve portrudes more out) because the tire pressure is low. Then, hook on the pump and start pumping. 

Otherwise, you can start with whatever pump you have and buy an extension hose or valve extender. The type of valve on there is a Schrader valve.