In a large pot, bring 4 cups of water to a boil over medium-high heat.
Add the halved potatoes to the boiling water and cook for about 10 minutes, or until they are just tender.
Stir in the sliced sausage and continue to cook for another 5 minutes.
Add the corn pieces and cook for an additional 5 minutes.
Sprinkle in the Old Bay seasoning, minced garlic, and salt. Stir well to combine.
Finally, add the shrimp and cook for 3-4 minutes, or until the shrimp turn pink and opaque.
Remove the pot from heat and squeeze the juice of the lemon halves over the mixture.
Carefully drain the pot and transfer the shrimp boil to a large serving platter.
Garnish with chopped parsley and serve hot with lemon wedges on the side.