The fat and membrane that tamsam mentioned is where that gamey flavor comes from. If you're hunting for food, bypass that trophy buck!
I've tried several recipes for summer sausage, some taking as long as 4 days. But, this is the one that the guys at deer camp seem to like, and it doesn't take very long:
2 lbs ground venison
2 TBS Tender Quick
1 TBS liquid smoke
1 TBS mustard seed
1/4 tsp salt
1/4 tsp pepper
1/4 tsp garlic salt
1/4 tsp onion powder
1 tsp garlic powder
1 Cup water
Mix all ingredients. Roll into 2-3 rolls and refrigerate a minimum of 24 hrs. Use pan on bottom shelf to catch fluids.
Place the rolls on oven rack in oven heated to 350 deg for about an hour. Longer if you make larger logs. Have a cookie sheet or something on the rack under them to catch fluids.
We up the amt of pepper and garlic... it's easy to adjust/add ingredients to your liking.
I wrap the rolls in tin foil, and punch little holes in the bottom of the foil to allow fluids to drain before puting them in the oven. The foil makes a softer casing, which is easier for the "older" guys to eat.