I tried a one wheel game carrier once to get an elk out. Even with two people, it barely worked and wore us both out. It got used for one load out and we switched to packs. It got returned. It would have worked very well on a dirt road going flat or down hill though. There's some videos on the mfg's website. Looks like it's only designed to haul 50 lbs. Videos address snow and sand. I'm questioning how it would be going up something steep , down something steep and if there was a tendency to drift off trail when sidehilling.
I think it looks like a great idea. It shows that if terrain gets too tough you can throw it on like a pack. Not inexpensive. I am fairly sure that it is not ok to use in wilderness areas due to the wheel. I know game carts are not ok in wilderness because they are considered mechanical.