We've been using different marinades over the years,to tenderize wild meat,both commercial and homemade recipes.Some were good,others not.Last year however,while camping with friends,they brought out some meat that was super tender and tasted great.It had been left in the simplest marinade and we've used it exclusively since then to marinate moose and elk and whatever else.It consists of adding soy sauce to vegtable cooking oil and then crushing some fresh garlic into it.That's it.We don't have to inject it but then we often leave the meat in the marinade for a week after bringing it out of the freezer before we cook it.
Dave