diff --git a/deno/lib/__tests__/object.test.ts b/deno/lib/__tests__/object.test.ts
index e3e161038..ba49e6339 100644
--- a/deno/lib/__tests__/object.test.ts
+++ b/deno/lib/__tests__/object.test.ts
@@ -229,7 +229,7 @@ test("inferred merged object type with optional properties", async () => {
     .object({ a: z.string(), b: z.string().optional() })
     .merge(z.object({ a: z.string().optional(), b: z.string() }));
   type Merged = z.infer<typeof Merged>;
-  util.assertEqual<Merged, { a: string | undefined; b: string }>(true);
+  util.assertEqual<Merged, { a?: string; b: string }>(true);
   // todo
   // util.assertEqual<Merged, { a?: string; b: string }>(true);
 });
diff --git a/deno/lib/types.ts b/deno/lib/types.ts
index b96af8059..420238114 100644
--- a/deno/lib/types.ts
+++ b/deno/lib/types.ts
@@ -2119,43 +2119,26 @@ export class ZodObject<
    */
   nonstrict = this.passthrough;
 
-  // augment = AugmentFactory<ZodObjectDef<T, UnknownKeys, Catchall>>(this._def);
-  // extend = AugmentFactory<ZodObjectDef<T, UnknownKeys, Catchall>>(this._def);
-  extend<
-    Augmentation extends ZodRawShape,
-    // NewShape extends extendShape<T, Augmentation>,
-    // OldOutput = util.flatten<Omit<Output, keyof Augmentation>>,
-    // AugOutput = baseObjectOutputType<Augmentation>,
-    // NewOutput = OldOutput & AugOutput,
-    NewOutput extends util.flatten<{
-      [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
-        ? Augmentation[k]["_output"]
-        : k extends keyof Output
-        ? Output[k]
-        : never;
-    }>,
-    // OldInput = util.flatten<Omit<Input, keyof Augmentation>>,
-    // AugInput = baseObjectInputType<Augmentation>,
-    // NewInput = OldInput & AugInput
-    NewInput extends util.flatten<{
-      [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
-        ? Augmentation[k]["_input"]
-        : k extends keyof Input
-        ? Input[k]
-        : never;
-    }>
-    // AKeys extends string | number | symbol = keyof Augmentation,
-
-    // AKeys extends string | number | symbol = keyof Augmentation
-  >(
+  // const AugmentFactory =
+  //   <Def extends ZodObjectDef>(def: Def) =>
+  //   <Augmentation extends ZodRawShape>(
+  //     augmentation: Augmentation
+  //   ): ZodObject<
+  //     extendShape<ReturnType<Def["shape"]>, Augmentation>,
+  //     Def["unknownKeys"],
+  //     Def["catchall"]
+  //   > => {
+  //     return new ZodObject({
+  //       ...def,
+  //       shape: () => ({
+  //         ...def.shape(),
+  //         ...augmentation,
+  //       }),
+  //     }) as any;
+  //   };
+  extend<Augmentation extends ZodRawShape>(
     augmentation: Augmentation
-  ): ZodObject<
-    extendShape<T, Augmentation>,
-    UnknownKeys,
-    Catchall,
-    NewOutput,
-    NewInput
-  > {
+  ): ZodObject<extendShape<T, Augmentation>, UnknownKeys, Catchall> {
     return new ZodObject({
       ...this._def,
       shape: () => ({
@@ -2164,6 +2147,39 @@ export class ZodObject<
       }),
     }) as any;
   }
+  // extend<
+  //   Augmentation extends ZodRawShape,
+  //   NewOutput extends util.flatten<{
+  //     [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_output"]
+  //       : k extends keyof Output
+  //       ? Output[k]
+  //       : never;
+  //   }>,
+  //   NewInput extends util.flatten<{
+  //     [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_input"]
+  //       : k extends keyof Input
+  //       ? Input[k]
+  //       : never;
+  //   }>
+  // >(
+  //   augmentation: Augmentation
+  // ): ZodObject<
+  //   extendShape<T, Augmentation>,
+  //   UnknownKeys,
+  //   Catchall,
+  //   NewOutput,
+  //   NewInput
+  // > {
+  //   return new ZodObject({
+  //     ...this._def,
+  //     shape: () => ({
+  //       ...this._def.shape(),
+  //       ...augmentation,
+  //     }),
+  //   }) as any;
+  // }
   /**
    * @deprecated Use `.extend` instead
    *  */
@@ -2174,49 +2190,13 @@ export class ZodObject<
    * inferred type of merged objects. Please
    * upgrade if you are experiencing issues.
    */
-  // merge<Incoming extends AnyZodObject>(merging: Incoming) {
-  //   return this.extend(merging.shape as Incoming["shape"]);
-  // }
-  merge<
-    Incoming extends AnyZodObject,
-    Augmentation extends Incoming["shape"],
-    // NewShape extends extendShape<T, Augmentation>,
-    // OldOutput = util.flatten<Omit<Output, keyof Augmentation>>,
-    // AugOutput = baseObjectOutputType<Augmentation>,
-    // NewOutput = OldOutput & AugOutput,
-    NewOutput extends {
-      [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
-        ? Augmentation[k]["_output"]
-        : k extends keyof Output
-        ? Output[k]
-        : never;
-    },
-    // OldInput = util.flatten<Omit<Input, keyof Augmentation>>,
-    // AugInput = baseObjectInputType<Augmentation>,
-    // NewInput = OldInput & AugInput
-    NewInput extends {
-      [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
-        ? Augmentation[k]["_input"]
-        : k extends keyof Input
-        ? Input[k]
-        : never;
-    }
-    // AKeys extends string | number | symbol = keyof Augmentation,
-
-    // AKeys extends string | number | symbol = keyof Augmentation
-  >(
+  merge<Incoming extends AnyZodObject, Augmentation extends Incoming["shape"]>(
     merging: Incoming
   ): ZodObject<
-    extendShape<T, ReturnType<Incoming["_def"]["shape"]>>,
+    extendShape<T, Augmentation>,
     Incoming["_def"]["unknownKeys"],
-    Incoming["_def"]["catchall"],
-    NewOutput,
-    NewInput
+    Incoming["_def"]["catchall"]
   > {
-    // const mergedShape = objectUtil.mergeShapes(
-    //   this._def.shape(),
-    //   merging._def.shape()
-    // );
     const merged: any = new ZodObject({
       unknownKeys: merging._def.unknownKeys,
       catchall: merging._def.catchall,
@@ -2226,6 +2206,41 @@ export class ZodObject<
     }) as any;
     return merged;
   }
+  // merge<
+  //   Incoming extends AnyZodObject,
+  //   Augmentation extends Incoming["shape"],
+  //   NewOutput extends {
+  //     [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_output"]
+  //       : k extends keyof Output
+  //       ? Output[k]
+  //       : never;
+  //   },
+  //   NewInput extends {
+  //     [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_input"]
+  //       : k extends keyof Input
+  //       ? Input[k]
+  //       : never;
+  //   }
+  // >(
+  //   merging: Incoming
+  // ): ZodObject<
+  //   extendShape<T, ReturnType<Incoming["_def"]["shape"]>>,
+  //   Incoming["_def"]["unknownKeys"],
+  //   Incoming["_def"]["catchall"],
+  //   NewOutput,
+  //   NewInput
+  // > {
+  //   const merged: any = new ZodObject({
+  //     unknownKeys: merging._def.unknownKeys,
+  //     catchall: merging._def.catchall,
+  //     shape: () =>
+  //       objectUtil.mergeShapes(this._def.shape(), merging._def.shape()),
+  //     typeName: ZodFirstPartyTypeKind.ZodObject,
+  //   }) as any;
+  //   return merged;
+  // }
 
   setKey<Key extends string, Schema extends ZodTypeAny>(
     key: Key,
diff --git a/package.json b/package.json
index 5ea82be17..a2fc21f48 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "zod",
-  "version": "3.20.5",
+  "version": "3.20.6",
   "description": "TypeScript-first schema declaration and validation library with static type inference",
   "main": "./lib/index.js",
   "types": "./index.d.ts",
diff --git a/playground.ts b/playground.ts
index 06eab0c20..73b6acd67 100644
--- a/playground.ts
+++ b/playground.ts
@@ -1,4 +1,6 @@
-// import { z } from "./src";
+import { z } from "./src";
+
+z.number().int();
 
 // const arg = z.enum(["a", "b"] as const);
 // const arb = arg.exclude(["b"]);
diff --git a/src/__tests__/object.test.ts b/src/__tests__/object.test.ts
index 67b3e4979..41c712c7b 100644
--- a/src/__tests__/object.test.ts
+++ b/src/__tests__/object.test.ts
@@ -228,7 +228,7 @@ test("inferred merged object type with optional properties", async () => {
     .object({ a: z.string(), b: z.string().optional() })
     .merge(z.object({ a: z.string().optional(), b: z.string() }));
   type Merged = z.infer<typeof Merged>;
-  util.assertEqual<Merged, { a: string | undefined; b: string }>(true);
+  util.assertEqual<Merged, { a?: string; b: string }>(true);
   // todo
   // util.assertEqual<Merged, { a?: string; b: string }>(true);
 });
diff --git a/src/types.ts b/src/types.ts
index 98dbd397a..c0c057f05 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -2119,43 +2119,26 @@ export class ZodObject<
    */
   nonstrict = this.passthrough;
 
-  // augment = AugmentFactory<ZodObjectDef<T, UnknownKeys, Catchall>>(this._def);
-  // extend = AugmentFactory<ZodObjectDef<T, UnknownKeys, Catchall>>(this._def);
-  extend<
-    Augmentation extends ZodRawShape,
-    // NewShape extends extendShape<T, Augmentation>,
-    // OldOutput = util.flatten<Omit<Output, keyof Augmentation>>,
-    // AugOutput = baseObjectOutputType<Augmentation>,
-    // NewOutput = OldOutput & AugOutput,
-    NewOutput extends util.flatten<{
-      [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
-        ? Augmentation[k]["_output"]
-        : k extends keyof Output
-        ? Output[k]
-        : never;
-    }>,
-    // OldInput = util.flatten<Omit<Input, keyof Augmentation>>,
-    // AugInput = baseObjectInputType<Augmentation>,
-    // NewInput = OldInput & AugInput
-    NewInput extends util.flatten<{
-      [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
-        ? Augmentation[k]["_input"]
-        : k extends keyof Input
-        ? Input[k]
-        : never;
-    }>
-    // AKeys extends string | number | symbol = keyof Augmentation,
-
-    // AKeys extends string | number | symbol = keyof Augmentation
-  >(
+  // const AugmentFactory =
+  //   <Def extends ZodObjectDef>(def: Def) =>
+  //   <Augmentation extends ZodRawShape>(
+  //     augmentation: Augmentation
+  //   ): ZodObject<
+  //     extendShape<ReturnType<Def["shape"]>, Augmentation>,
+  //     Def["unknownKeys"],
+  //     Def["catchall"]
+  //   > => {
+  //     return new ZodObject({
+  //       ...def,
+  //       shape: () => ({
+  //         ...def.shape(),
+  //         ...augmentation,
+  //       }),
+  //     }) as any;
+  //   };
+  extend<Augmentation extends ZodRawShape>(
     augmentation: Augmentation
-  ): ZodObject<
-    extendShape<T, Augmentation>,
-    UnknownKeys,
-    Catchall,
-    NewOutput,
-    NewInput
-  > {
+  ): ZodObject<extendShape<T, Augmentation>, UnknownKeys, Catchall> {
     return new ZodObject({
       ...this._def,
       shape: () => ({
@@ -2164,6 +2147,39 @@ export class ZodObject<
       }),
     }) as any;
   }
+  // extend<
+  //   Augmentation extends ZodRawShape,
+  //   NewOutput extends util.flatten<{
+  //     [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_output"]
+  //       : k extends keyof Output
+  //       ? Output[k]
+  //       : never;
+  //   }>,
+  //   NewInput extends util.flatten<{
+  //     [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_input"]
+  //       : k extends keyof Input
+  //       ? Input[k]
+  //       : never;
+  //   }>
+  // >(
+  //   augmentation: Augmentation
+  // ): ZodObject<
+  //   extendShape<T, Augmentation>,
+  //   UnknownKeys,
+  //   Catchall,
+  //   NewOutput,
+  //   NewInput
+  // > {
+  //   return new ZodObject({
+  //     ...this._def,
+  //     shape: () => ({
+  //       ...this._def.shape(),
+  //       ...augmentation,
+  //     }),
+  //   }) as any;
+  // }
   /**
    * @deprecated Use `.extend` instead
    *  */
@@ -2174,49 +2190,13 @@ export class ZodObject<
    * inferred type of merged objects. Please
    * upgrade if you are experiencing issues.
    */
-  // merge<Incoming extends AnyZodObject>(merging: Incoming) {
-  //   return this.extend(merging.shape as Incoming["shape"]);
-  // }
-  merge<
-    Incoming extends AnyZodObject,
-    Augmentation extends Incoming["shape"],
-    // NewShape extends extendShape<T, Augmentation>,
-    // OldOutput = util.flatten<Omit<Output, keyof Augmentation>>,
-    // AugOutput = baseObjectOutputType<Augmentation>,
-    // NewOutput = OldOutput & AugOutput,
-    NewOutput extends {
-      [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
-        ? Augmentation[k]["_output"]
-        : k extends keyof Output
-        ? Output[k]
-        : never;
-    },
-    // OldInput = util.flatten<Omit<Input, keyof Augmentation>>,
-    // AugInput = baseObjectInputType<Augmentation>,
-    // NewInput = OldInput & AugInput
-    NewInput extends {
-      [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
-        ? Augmentation[k]["_input"]
-        : k extends keyof Input
-        ? Input[k]
-        : never;
-    }
-    // AKeys extends string | number | symbol = keyof Augmentation,
-
-    // AKeys extends string | number | symbol = keyof Augmentation
-  >(
+  merge<Incoming extends AnyZodObject, Augmentation extends Incoming["shape"]>(
     merging: Incoming
   ): ZodObject<
-    extendShape<T, ReturnType<Incoming["_def"]["shape"]>>,
+    extendShape<T, Augmentation>,
     Incoming["_def"]["unknownKeys"],
-    Incoming["_def"]["catchall"],
-    NewOutput,
-    NewInput
+    Incoming["_def"]["catchall"]
   > {
-    // const mergedShape = objectUtil.mergeShapes(
-    //   this._def.shape(),
-    //   merging._def.shape()
-    // );
     const merged: any = new ZodObject({
       unknownKeys: merging._def.unknownKeys,
       catchall: merging._def.catchall,
@@ -2226,6 +2206,41 @@ export class ZodObject<
     }) as any;
     return merged;
   }
+  // merge<
+  //   Incoming extends AnyZodObject,
+  //   Augmentation extends Incoming["shape"],
+  //   NewOutput extends {
+  //     [k in keyof Augmentation | keyof Output]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_output"]
+  //       : k extends keyof Output
+  //       ? Output[k]
+  //       : never;
+  //   },
+  //   NewInput extends {
+  //     [k in keyof Augmentation | keyof Input]: k extends keyof Augmentation
+  //       ? Augmentation[k]["_input"]
+  //       : k extends keyof Input
+  //       ? Input[k]
+  //       : never;
+  //   }
+  // >(
+  //   merging: Incoming
+  // ): ZodObject<
+  //   extendShape<T, ReturnType<Incoming["_def"]["shape"]>>,
+  //   Incoming["_def"]["unknownKeys"],
+  //   Incoming["_def"]["catchall"],
+  //   NewOutput,
+  //   NewInput
+  // > {
+  //   const merged: any = new ZodObject({
+  //     unknownKeys: merging._def.unknownKeys,
+  //     catchall: merging._def.catchall,
+  //     shape: () =>
+  //       objectUtil.mergeShapes(this._def.shape(), merging._def.shape()),
+  //     typeName: ZodFirstPartyTypeKind.ZodObject,
+  //   }) as any;
+  //   return merged;
+  // }
 
   setKey<Key extends string, Schema extends ZodTypeAny>(
     key: Key,