diff --git a/src/Bytecode/Instruction/execute.c b/src/Bytecode/Instruction/execute.c
index a2e2dbf..b50b1e2 100644
--- a/src/Bytecode/Instruction/execute.c
+++ b/src/Bytecode/Instruction/execute.c
@@ -913,7 +913,24 @@ struct GroundExecutionResult _GroundBytecodeInstructionExecute(GroundBytecodeIns
                     GroundBytecodeValue* type = HEAP_GET(heap, instruction->args.at[i]);
                     switch (type->type.type) {
                         case GroundType_Struct: {
-                            // TODO nested structs
+                            GroundBytecodeStruct* innerStruct = &type->as.Struct;
+                            GroundBytecodeObject nestedObject = {
+                                .size = innerStruct->size,
+                                .capacity = innerStruct->size,
+                                .values = malloc(sizeof(GroundBytecodeValue) * innerStruct->size)
+                            };
+                            if (nestedObject.values == NULL) {
+                                Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
+                                Ground.Flags.error = true;
+                                return CONTINUE;
+                            }
+                            for (GroundSize k = 0; k < innerStruct->size; k++) {
+                                nestedObject.values[k] = Ground.Copy.BytecodeValue(&innerStruct->values[k]);
+                            }
+                            gbs->values[offset] = (GroundBytecodeValue) {
+                                .as.Object = nestedObject,
+                                .type = {GroundType_Object}
+                            };
                             break;
                         }
                         case GroundType_CoreType: {
@@ -1054,6 +1071,22 @@ struct GroundExecutionResult _GroundBytecodeInstructionExecute(GroundBytecodeIns
         return CONTINUE;
     }
     SETFIELD: {
+        // args: [parent_offset, field0_offset, ..., fieldF_offset, value_offset]
+        GroundBytecodeValue* current = HEAP_GET(heap, instruction->args.at[0]);
+
+        for (GroundSize i = 1; i < instruction->args.len - 1; i++) {
+            if (current->type.type != GroundType_Object) {
+                Ground.Log.Error("SETFIELD on non-object value in Ground.Bytecode.Instruction.execute");
+                Ground.Flags.error = true;
+                return CONTINUE;
+            }
+            current = &current->as.Object.values[instruction->args.at[i]];
+        }
+
+        GroundBytecodeValue* value = HEAP_GET(heap, instruction->args.at[instruction->args.len - 1]);
+        Ground.Free.BytecodeValue(current);
+        *current = Ground.Copy.BytecodeValue(value);
+
         return CONTINUE;
     }
     USE: {
diff --git a/src/Free/Arg.c b/src/Free/Arg.c
index 87ace8d..1e5f811 100644
--- a/src/Free/Arg.c
+++ b/src/Free/Arg.c
@@ -3,7 +3,7 @@
 void _GroundFreeArg(GroundArg* in) {
     if (in->type == GroundArg_Value) {
         Ground.Free.Value(&in->as.value);
-    } else {
+    } else if (in->type != GroundArg_DirectRef && in->type != GroundArg_Label && in->type != GroundArg_LineRef) {
         Ground.Free.Identifier(in->as.ref);
     }
 }
diff --git a/src/New/Bytecode.c b/src/New/Bytecode.c
index 0211ed3..4b0a854 100644
--- a/src/New/Bytecode.c
+++ b/src/New/Bytecode.c
@@ -106,15 +106,49 @@ static inline GroundSize doOffsets(GroundProgram* gp, GroundState* state, Ground
                 
                 // Set offset for each struct field 
                 GroundObjectField *s, *tmp;
-                GroundSize i = 0;
+                GroundSize fi = 0;
                 HASH_ITER(hh, gs->fields, s, tmp) {
-                    s->offset = i++;
+                    s->offset = fi++;
                 }
 
+                // Create bytecode instruction
+                GroundBytecodeInstruction newInst = {
+                    .type = GroundInstruction_STRUCT,
+                    .args = {
+                        .at = malloc(sizeof(GroundSize) * inst->args.len),
+                        .capacity = inst->args.len,
+                        .len = inst->args.len
+                    }
+                };
+
+                if (newInst.args.at == NULL) {
+                    Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
+                    Ground.Flags.error = true;
+                    return 0;
+                }
+
+                // Resolve the struct type variable to a heap offset
+                GroundArg* arg = &inst->args.at[0];
+                GroundVariable* structItem = NULL;
+                HASH_FIND_STR(state->variables, arg->as.ref->string, structItem);
+                if (structItem == NULL) {
+                    structItem = malloc(sizeof(GroundVariable));
+                    if (structItem == NULL) {
+                        Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
+                        Ground.Flags.error = true;
+                        return 0;
+                    }
+                    structItem->value = Ground.New.Value.Int(0);
+                    strncpy(structItem->name, arg->as.ref->string, 2047);
+                    structItem->_offset = size++;
+                    HASH_ADD_STR(state->variables, name, structItem);
+                }
+                newInst.args.at[0] = structItem->_offset;
+
                 // Now go through and add offsets to everything (skip struct name at index 0)
                 for (GroundSize j = 1; j < inst->args.len; j++) {
                     // struct field name
-                    GroundArg* arg = &inst->args.at[j];
+                    arg = &inst->args.at[j];
                     GroundObjectField* field = NULL;
                     HASH_FIND_STR(gs->fields, arg->as.ref->string, field);
                     if (field == NULL) {
@@ -122,40 +156,61 @@ static inline GroundSize doOffsets(GroundProgram* gp, GroundState* state, Ground
                         Ground.Flags.error = true;
                         return 0;
                     }
-                    arg->_offset = field->offset;
-                    // 2nd arg offset is already set, but what we do next depends on it
+                    newInst.args.at[j] = field->offset;
+                    // 2nd arg is the op code, what we do next depends on it
                     j++;
                     // 0 -> none
                     // 1 -> init 
                     // 2 -> set
                     // 3 -> attach closure to function
-                    switch (inst->args.at[j]._offset) {
+                    GroundSize op = inst->args.at[j]._offset;
+                    newInst.args.at[j] = op;
+                    switch (op) {
                         case 0: case 3: break; // these do not require extra values
                         case 1:                // but these do, so we process them
-                        case 2: {              // it's safe to assume that literals will have
-                            j++;               // been dealt with accordingly
+                        case 2: {
+                            j++;
                             arg = &inst->args.at[j];
                             GroundVariable* item = NULL;
-                            HASH_FIND_STR(state->variables, arg->as.ref->string, item);
 
-                            if (item == NULL) {
+                            if (arg->type == GroundArg_Value) {
+                                // Literal value: create a constant variable for it
                                 item = malloc(sizeof(GroundVariable));
                                 if (item == NULL) {
                                     Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
                                     Ground.Flags.error = true;
                                     return 0;
                                 }
-                                item->value = Ground.New.Value.Int(0);
-                                strncpy(item->name, arg->as.ref->string, 2047);
+                                item->value = Ground.Copy.Value(&arg->as.value);
                                 item->_offset = size++;
+                                snprintf(item->name, sizeof(item->name) - 1, "_._.ground_internal_constant_%zu", item->_offset);
                                 HASH_ADD_STR(state->variables, name, item);
+                            } else {
+                                // Variable reference: look it up or create it
+                                HASH_FIND_STR(state->variables, arg->as.ref->string, item);
+
+                                if (item == NULL) {
+                                    item = malloc(sizeof(GroundVariable));
+                                    if (item == NULL) {
+                                        Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
+                                        Ground.Flags.error = true;
+                                        return 0;
+                                    }
+                                    item->value = Ground.New.Value.Int(0);
+                                    strncpy(item->name, arg->as.ref->string, 2047);
+                                    item->_offset = size++;
+                                    HASH_ADD_STR(state->variables, name, item);
+                                }
                             }
 
-                            arg->_offset = item->_offset;
+                            newInst.args.at[j] = item->_offset;
                         }
                     }
                 }
 
+                gbp->at[i] = newInst;
+                gbp->len++;
+
                 continue;
             }
             case GroundInstruction_GETFIELD: {
@@ -274,6 +329,114 @@ static inline GroundSize doOffsets(GroundProgram* gp, GroundState* state, Ground
                 continue;
             }
             case GroundInstruction_SETFIELD: {
+                // setfield $parent -type (&field -type)... &field $value
+                // Bytecode: parent_offset, field0_offset, ..., fieldF_offset, value_offset
+                GroundInstruction* inst = &gp->at[i];
+                GroundSize gbiSize = 2 + ((inst->args.len - 2) / 2);
+
+                GroundBytecodeInstruction newInst = {
+                    .type = GroundInstruction_SETFIELD,
+                    .args = {
+                        .at = malloc(sizeof(GroundSize) * gbiSize),
+                        .capacity = gbiSize,
+                        .len = gbiSize
+                    }
+                };
+
+                if (newInst.args.at == NULL) {
+                    Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
+                    Ground.Flags.error = true;
+                    return 0;
+                }
+
+                // Resolve the parent variable to a heap offset
+                GroundArg* arg = &inst->args.at[0];
+
+                GroundVariable* item = NULL;
+                HASH_FIND_STR(state->variables, arg->as.ref->string, item);
+
+                if (item == NULL) {
+                    item = malloc(sizeof(GroundVariable));
+                    if (item == NULL) {
+                        Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
+                        Ground.Flags.error = true;
+                        return 0;
+                    }
+                    item->value = Ground.New.Value.Int(0);
+                    strncpy(item->name, arg->as.ref->string, 2047);
+                    item->_offset = size++;
+                    HASH_ADD_STR(state->variables, name, item);
+                }
+
+                newInst.args.at[0] = item->_offset;
+
+                // Get the type of the parent (type annotation is at args[1])
+                GroundVariable* var = NULL;
+                HASH_FIND_STR(state->variables, inst->args.at[1].as.ref->string, var);
+                if (var == NULL) {
+                    Ground.Log.Error("unknown struct name in Ground.New.Bytecode -> doOffsets");
+                    Ground.Flags.error = true;
+                    return 0;
+                }
+                if (var->value.type.type != GroundType_Struct) {
+                    Ground.Log.Error("known name is not a struct in Ground.New.Bytecode -> doOffsets");
+                    Ground.Flags.error = true;
+                    return 0;
+                }
+
+                GroundStruct* currentType = &var->value.as.Struct;
+
+                // Resolve each field's offset within its containing struct
+                for (GroundSize j = 0; j < gbiSize - 2; j++) {
+                    GroundArg* arg = &inst->args.at[2 + (j * 2)];
+
+                    GroundObjectField* field;
+                    HASH_FIND_STR(currentType->fields, arg->as.ref->string, field);
+                    if (field == NULL) {
+                        Ground.Log.Error("unknown field in struct in Ground.New.Bytecode -> doOffsets");
+                        Ground.Flags.error = true;
+                        return 0;
+                    }
+                    newInst.args.at[1 + j] = field->offset;
+
+                    // Resolve the type for the next field (not needed for the last field)
+                    if (j < gbiSize - 3) {
+                        GroundVariable* typeVar = NULL;
+                        HASH_FIND_STR(state->variables, inst->args.at[3 + j * 2].as.ref->string, typeVar);
+                        if (typeVar == NULL) {
+                            Ground.Log.Error("unknown struct type for field in Ground.New.Bytecode -> doOffsets");
+                            Ground.Flags.error = true;
+                            return 0;
+                        }
+                        if (typeVar->value.type.type != GroundType_Struct) {
+                            Ground.Log.Error("field type is not a struct in Ground.New.Bytecode -> doOffsets");
+                            Ground.Flags.error = true;
+                            return 0;
+                        }
+                        currentType = &typeVar->value.as.Struct;
+                    }
+                }
+
+                // Resolve the value variable
+                GroundArg* valueArg = &inst->args.at[inst->args.len - 1];
+                GroundVariable* valueItem = NULL;
+                HASH_FIND_STR(state->variables, valueArg->as.ref->string, valueItem);
+                if (valueItem == NULL) {
+                    valueItem = malloc(sizeof(GroundVariable));
+                    if (valueItem == NULL) {
+                        Ground.Log.Error("malloc failed in Ground.New.Bytecode -> doOffsets");
+                        Ground.Flags.error = true;
+                        return 0;
+                    }
+                    valueItem->value = Ground.New.Value.Int(0);
+                    strncpy(valueItem->name, valueArg->as.ref->string, 2047);
+                    valueItem->_offset = size++;
+                    HASH_ADD_STR(state->variables, name, valueItem);
+                }
+                newInst.args.at[gbiSize - 1] = valueItem->_offset;
+
+                gbp->at[i] = newInst;
+                gbp->len++;
 
                 continue;
             }
diff --git a/src/Program/preprocess.c b/src/Program/preprocess.c
index 86b1f45..f3cfee2 100644
--- a/src/Program/preprocess.c
+++ b/src/Program/preprocess.c
@@ -246,6 +246,8 @@ static void doStruct(GroundProgram* program, GroundProgram* newProgram, GroundSt
 
     }
 
+    Ground.Program.append(newProgram, output);
+
     GroundVariable* variable = malloc(sizeof(GroundVariable));
     if (variable == NULL) {
         Ground.Log.Error("malloc failed in Ground.Program.Preprocess -> doStruct");
diff --git a/src/Stringify/BytecodeValue.c b/src/Stringify/BytecodeValue.c
index 284a4af..8bbfbd9 100644
--- a/src/Stringify/BytecodeValue.c
+++ b/src/Stringify/BytecodeValue.c
@@ -65,11 +65,11 @@ char* _GroundStringifyBytecodeValue(GroundBytecodeValue* value) {
         }
         case GroundType_Object: {
             Estr str = CREATE_ESTR("<object fields: { ");
-            for (GroundSize i = 0; i < value->as.Struct.size; i++) {
+            for (GroundSize i = 0; i < value->as.Object.size; i++) {
                 if (i != 0) {
                     APPEND_ESTR(str, ", ");
                 }
-                char* field = Ground.Stringify.BytecodeValue(&value->as.Struct.values[i]);
+                char* field = Ground.Stringify.BytecodeValue(&value->as.Object.values[i]);
                 APPEND_ESTR(str, field);
                 free(field);
             }