Preheat oven to 350. Line an 8×8" pan with aluminum foil (the nonstick kind if you have it) and spray lightly with cooking spray.
Melt butter in small dish, in microwave for about 60 - 90 seconds.
Add the brown sugar, vanilla, and whisk until smooth and combined.
Add the flour, oats, baking soda, 1/4 tsp salt, and stir with rubber spatula until combined.
Add half of the oat mixture to the prepared pan, press it with spatula or fingers, into an even layer.
Bake for 10 minutes. While it bakes, make the caramel sauce.
In a bowl, combine the unwrapped caramels, cream, and microwave for 4 minutes, stirring every 60 seconds, until the sauce is smooth and easy to stir. Add 1/2 tsp salt and stir.
After 10 minutes, remove pan from the oven and sprinkle chocolate chips over the oats.
Carefully pour the caramel sauce over the chocolate.
Crumble remaining oat mixture over the top (or press it into a smooth layer).
Place in oven and bake for about 18 minutes (yours might be done sooner, start checking after about 15 minutes), or until edges are lightly browned and center is just set.
Melt milk chocolate and drizzle over the top of the bars.
Let bars to cool completely in the pan before slicing or else the hot caramel and chocolate will run everywhere. Mine took about 2-3 hours. You could also put the pan in the refrigerator, covered, to speed up the cooling process.