Preheat oven to 425˚F.
In a mixing bowl combine the halved potatoes and the corn rounds.
In a separate mixing bowl combine the sausage and shrimp.
Melt the butter, then stir in the minced garlic, old bay seasoning, and cajun seasoning.
Add about half of the melted butter mixture to the potatoes and corn; toss to coat.
Transfer the potatoes and corn to a large rimmed baking sheet and bake for 18 minutes, stirring halfway through cooking.
In the meantime, add the remaining butter mixture to the sausages and shrimp; toss to coat.
When the 18 minutes is up, pull out the baking sheet from the oven and arrange the sausages and shrimp around the potatoes and corn.
Continue to bake for 8 to 10 more minutes, or until shrimp are opaque and corn is tender.
Remove from oven.
Garnish with parsley.
Serve with lemon wedges.