diff --git a/src/config.c b/src/config.c
index dcb6b9d..f320f33 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1,3 +1,8 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <getopt.h>
+
 #include "config.h"
 
 Config config = {
@@ -7,23 +12,67 @@ Config config = {
     .ui_font2 = "/usr/share/fonts/TTF/unifont.ttf",
     .ui_font_size1 = 6,
     .ui_font_size2 = 4,
-    .real_speed = true,
-    .verbose = true,
+    .throttle = false,
+    .verbose = false,
+    .allow_shutdn = false,
 };
 
 void parse_args( int argc, char* argv[] )
 {
-    while ( --argc ) {
-        argv++;
-        if ( argv[ 0 ][ 0 ] == '-' ) {
-            switch ( argv[ 0 ][ 1 ] ) {
-                case 't':
-                    config.real_speed = true;
-                    break;
-                case 'r':
-                    config.real_speed = false;
-                    break;
-            }
+    int option_index;
+    int c = '?';
+    char* optstring = "hVs:";
+    struct option long_options[] = {
+        {"help",           no_argument,       NULL, 'h' },
+        {"verbose",        no_argument,       NULL, 'V' },
+        {"scale",          required_argument, NULL, 's' },
+        {"throttle",       no_argument,       NULL, 1800},
+        {"allow-shutdown", no_argument,       NULL, 1900},
+
+        {0,                0,                 0,    0   }
+    };
+
+    char* help_text = "usage: %s [options]\n"
+                      "options:\n"
+                      "  -h --help               what you are reading\n"
+                      "  -V --verbose            be verbose (default: false)\n"
+                      "  -s --scale=<i>          scale GUI (default: 3)\n"
+                      "     --throttle           Throttle speed (default: false)\n"
+                      "     --allow-shutdown     Enable SHUTDN instruction (default: false)\n";
+    while ( c != EOF ) {
+        c = getopt_long( argc, argv, optstring, long_options, &option_index );
+
+        switch ( c ) {
+            case 'h':
+                fprintf( stderr, help_text, config.progname );
+                exit( 0 );
+                break;
+            case 's':
+                config.ui_scale = atoi( optarg );
+                break;
+            case 'V':
+                config.verbose = true;
+                break;
+            case 1800:
+                config.throttle = true;
+                break;
+            case 1900:
+                config.allow_shutdn = true;
+                break;
+
+            case '?':
+            case ':':
+                exit( 0 );
+                break;
+            default:
+                break;
         }
     }
+
+    if ( optind < argc ) {
+        fprintf( stderr, "Invalid arguments : " );
+        while ( optind < argc )
+            fprintf( stderr, "%s\n", argv[ optind++ ] );
+        fprintf( stderr, "\n" );
+    }
 }
diff --git a/src/config.h b/src/config.h
index efd3d27..b24ba05 100644
--- a/src/config.h
+++ b/src/config.h
@@ -10,8 +10,9 @@ typedef struct {
     char* ui_font2;
     int ui_font_size1;
     int ui_font_size2;
-    bool real_speed;
+    bool throttle;
     bool verbose;
+    bool allow_shutdn;
 } Config;
 
 extern Config config;
diff --git a/src/emulator.c b/src/emulator.c
index 8d1e8cf..9928be0 100644
--- a/src/emulator.c
+++ b/src/emulator.c
@@ -117,7 +117,7 @@ bool emulator_run( void )
         if ( !cpu.shutdown ) {
             execute_instruction();
 
-            throttle( config.real_speed || cpu.keyintp );
+            throttle( config.throttle || cpu.keyintp );
 
             if ( emulator_state == EMULATOR_STEP )
                 emulator_set_state( EMULATOR_STOP );
diff --git a/src/opcodes.c b/src/opcodes.c
index fa6054c..e91c9c0 100644
--- a/src/opcodes.c
+++ b/src/opcodes.c
@@ -1,6 +1,7 @@
 #include <string.h>
 
 #include "types.h"
+#include "config.h"
 #include "cpu.h"
 #include "bus.h"
 #include "keyboard.h"
@@ -367,9 +368,8 @@ static void op806( byte* opc ) // C=ID
 static void op807( byte* opc ) // SHUTDN
 {
     // TODO: Fix SHUTDN
-    /* if ( !cpu.in[ 0 ] && !cpu.in[ 1 ] && !cpu.in[ 3 ] ) { */
-    /*     cpu.shutdown = true; */
-    /* } */
+    cpu.shutdown = config.allow_shutdn && ( !cpu.in[ 0 ] && !cpu.in[ 1 ] && !cpu.in[ 3 ] );
+
     cpu.pc += 3;
     cpu.cycles += 5;
 }