diff --git a/changelog.md b/changelog.md
index a8d0b56..199d5d5 100644
--- a/changelog.md
+++ b/changelog.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - update default retroarch-emscripten-build version to v1.17.0
 - disable some default inputs in RetroArch
+- when some of the passed config items are objects, like `retroarchConfig`, they will be merged with the default items instead of overwriting the default items entirely
 
 ### Fixed
 - fix export name when using ESM build of retroarch
diff --git a/src/nostalgist.ts b/src/nostalgist.ts
index dd12379..60116f9 100644
--- a/src/nostalgist.ts
+++ b/src/nostalgist.ts
@@ -10,6 +10,7 @@ import type {
   NostalgistOptionsPartial,
   NostalgistResolveFileFunction,
 } from './types/nostalgist-options'
+import { merge } from './utils'
 import { vendors } from './vendors'
 
 function baseName(url: string) {
@@ -29,10 +30,9 @@ export class Nostalgist {
   private emulator: Emulator | undefined
 
   private constructor(options: NostalgistLaunchOptions) {
-    const mergedOptions = {
-      ...Nostalgist.globalOptions,
-      ...options,
-    }
+    const mergedOptions = {}
+    merge(mergedOptions, Nostalgist.globalOptions, options)
+    // @ts-expect-error we cannot infer the final type here
     this.options = mergedOptions
   }
 
@@ -59,10 +59,7 @@ export class Nostalgist {
    * ```
    */
   static configure(options: NostalgistOptionsPartial) {
-    Nostalgist.globalOptions = {
-      ...Nostalgist.globalOptions,
-      ...options,
-    }
+    merge(Nostalgist.globalOptions, options)
   }
 
   /**
@@ -477,10 +474,8 @@ export class Nostalgist {
     }
 
     if (element) {
-      return {
-        ...defaultAppearanceStyle,
-        ...style,
-      }
+      merge(defaultAppearanceStyle, style)
+      return defaultAppearanceStyle
     }
 
     const defaultLayoutStyle: Partial<CSSStyleDeclaration> = {
@@ -491,11 +486,8 @@ export class Nostalgist {
       height: '100%',
       zIndex: '1',
     }
-    return {
-      ...defaultLayoutStyle,
-      ...defaultAppearanceStyle,
-      ...style,
-    }
+    merge(defaultLayoutStyle, defaultAppearanceStyle, style)
+    return defaultLayoutStyle
   }
 
   private async getCoreOption() {
@@ -610,17 +602,15 @@ export class Nostalgist {
   }
 
   private getRetroarchOption() {
-    return {
-      ...Nostalgist.globalOptions.retroarchConfig,
-      ...this.options.retroarchConfig,
-    }
+    const options = {}
+    merge(options, Nostalgist.globalOptions.retroarchConfig, this.options.retroarchConfig)
+    return options as typeof this.options.retroarchConfig
   }
 
   private getRetroarchCoreOption() {
-    return {
-      ...Nostalgist.globalOptions.retroarchCoreConfig,
-      ...this.options.retroarchCoreConfig,
-    }
+    const options = {}
+    merge(options, Nostalgist.globalOptions.retroarchCoreConfig, this.options.retroarchCoreConfig)
+    return options
   }
 
   private loadEmulator() {
diff --git a/src/utils.ts b/src/utils.ts
index ebe4a5e..a5c520e 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -98,3 +98,39 @@ export async function importCoreJsAsESM({ name, js }: { name: string; js: string
     URL.revokeObjectURL(jsBlobUrl)
   }
 }
+
+function isNil(obj: unknown) {
+  return obj === undefined || obj === null
+}
+
+function isPrimitive(obj: unknown) {
+  if (isNil(obj)) {
+    return true
+  }
+  const type = typeof obj
+  const primitevTypes = ['string', 'number', 'boolean', 'bigint', 'symbol', 'function']
+  return primitevTypes.includes(type)
+}
+
+function mergeSourceToTarget(target: any, source: any) {
+  for (const key in source) {
+    if (Object.prototype.hasOwnProperty.call(source, key)) {
+      const targetValue = target[key]
+      const sourceValue = source[key]
+      if (isPrimitive(sourceValue)) {
+        target[key] = sourceValue
+      } else if (Array.isArray(targetValue) && Array.isArray(sourceValue)) {
+        target[key] = [...targetValue, ...sourceValue]
+      } else {
+        target[key] = isPrimitive(targetValue) ? {} : target[key]
+        merge(target[key], sourceValue)
+      }
+    }
+  }
+}
+
+export function merge(target: any, ...sources: any[]) {
+  for (const source of sources) {
+    mergeSourceToTarget(target, source)
+  }
+}
diff --git a/tests/integration/nostalgist.spec.ts b/tests/integration/nostalgist.spec.ts
index 100878d..4ac5f9f 100644
--- a/tests/integration/nostalgist.spec.ts
+++ b/tests/integration/nostalgist.spec.ts
@@ -203,4 +203,29 @@ describe('nostalgist', () => {
       expect(file.fileContent.size).toBeGreaterThan(0)
     }
   })
+
+  test.only('Nostalgist.launch with nested options', async () => {
+    Nostalgist.configure({
+      retroarchConfig: {
+        input_audio_mute: 'a',
+        input_menu_toggle: 'nul',
+      },
+    })
+
+    const nostalgist = await Nostalgist.launch({
+      core: 'fceumm',
+      rom: 'flappybird.nes',
+      retroarchConfig: {
+        input_max_users: 4,
+        input_audio_mute: 'b',
+      },
+    })
+
+    const options = nostalgist.getOptions()
+    expect(options.retroarchConfig).toMatchObject({
+      menu_driver: 'rgui',
+      input_menu_toggle: 'nul',
+      input_audio_mute: 'b',
+    })
+  })
 })