diff --git a/engine.ps1 b/engine.ps1
index 4b363df..5e5b95d 100644
--- a/engine.ps1
+++ b/engine.ps1
@@ -97,10 +97,16 @@ function Merge-Config($base, $override) {
     if (-not $override) { return $base }
     $merged = $base | ConvertTo-Json -Depth 10 | ConvertFrom-Json
     foreach ($section in $override.PSObject.Properties) {
-        if ($null -ne $merged.PSObject.Properties[$section.Name]) {
+        if ($section.Name -like "_*") { continue }
+        $baseSection = $merged.PSObject.Properties[$section.Name]
+        if ($null -eq $baseSection) {
+            $merged | Add-Member -NotePropertyName $section.Name -NotePropertyValue $section.Value
+        } elseif ($section.Value -is [System.Management.Automation.PSCustomObject]) {
             foreach ($prop in $section.Value.PSObject.Properties) {
-                $merged.$($section.Name).$($prop.Name) = $prop.Value
+                $merged.$($section.Name) | Add-Member -NotePropertyName $prop.Name -NotePropertyValue $prop.Value -Force
             }
+        } else {
+            $merged.$($section.Name) = $section.Value
         }
     }
     return $merged