Yep, my first one took me probably 30 minutes to an hour. Many years and many deer later, it now takes me about 3 minutes (including a coffee break) - goes about like this:
Flip deer on back, and split the belly open from ribcage to pelvis (30 seconds, maybe less if I have a gut-hook handy).
Flip deer on to side, cut through diaphragm, and carefully reach up into chest cavity with both arms (and a knife), grab windpipe with one hand, cut wind-pipe up above that hand with kinfe (30 seconds)
Use now severed windpipe for a handle and pull hard on innards, using knife to cut loose any spots that hang up and don't tear loose with vigorous pulling/yanking until guts are all laying on the ground beside the deer (30 seconds).
Stop and sip coffee, wipe blood off of hands, observe results of bullet performance on innards, and make celebratory comments to hunting partner(s) (if any) (60 seconds)
Reach down and cut entrails off so about 10 inches of poop tube hangs out of the body cavity. Tie off poop tube so poop doesn't get on critter during trip home. (30 seconds).
Done - one field dressed deer, ready for hauling/dragging to a more convenient place to string him up for skinning and final preperation of the meat before hanging it to age a bit.