diff --git a/RetroUFO_GUI.py b/RetroUFO_GUI.py
index 6dc8d08..33375fc 100644
--- a/RetroUFO_GUI.py
+++ b/RetroUFO_GUI.py
@@ -7,12 +7,26 @@ __author__ = "Melon Bread"
 __version__ = "0.8.0"
 __license__ = "MIT"
 
+import argparse
+import os
+import platform
 import sys
-
+import zipfile
+from pathlib import Path
+from shutil import rmtree
+from urllib.request import urlretrieve
 from PySide2.QtWidgets import QApplication, QDialog, QLineEdit, QComboBox, QCheckBox, QPushButton, QFileDialog, \
     QVBoxLayout, QTextEdit
 
 
+URL = 'https://buildbot.libretro.com/nightly'
+
+# These are the default core locations with normal RetroArch installs based off of 'retroarch.default.cfg`
+CORE_LOCATION = {
+    'linux': '{}/.config/retroarch/cores'.format(Path.home()),
+    'windows': '{}/AppData/Roaming/RetroArch/cores'.format(Path.home())
+}
+
 class Form(QDialog):
 
     def __init__(self, parent=None):
@@ -43,9 +57,13 @@ class Form(QDialog):
 
         self.teditLog = QTextEdit()
         self.teditLog.setReadOnly(True)
+        
+        self.chkboxKeepDownload = QCheckBox('Keep Downloaded Cores')
+        self.chkboxKeepDownload.setChecked(False)
+
 
         self.btnGrabCores = QPushButton('Grab Cores')
-        self.btnGrabCores.clicked.connect(self.download_cores())
+        self.btnGrabCores.clicked.connect(self.grab_cores)
 
         # Create layout and add widgets
         layout = QVBoxLayout()
@@ -55,6 +73,7 @@ class Form(QDialog):
         layout.addWidget(self.leditCoreLocation)
         layout.addWidget(self.btnCoreLocation)
         layout.addWidget(self.teditLog)
+        layout.addWidget(self.chkboxKeepDownload)
         layout.addWidget(self.btnGrabCores)
 
         # Set dialog layout
@@ -79,8 +98,90 @@ class Form(QDialog):
 
         self.leditCoreLocation.insert(directory)
 
-    def download_cores(self):
-        pass
+    def grab_cores(self):
+        self.teditLog.insertPlainText('Starting UFO Grabber')
+        """ Where the magic happens """
+
+        # If a platform and/or architecture is not supplied it is grabbed automatically
+        platform = self.get_platform()  # TODO: rename this var to prevent conflict
+        architecture = self.get_architecture()
+        location = CORE_LOCATION[platform]
+
+        self.download_cores(platform, architecture)
+        self.extract_cores(location)
+
+        if not args.keep:
+            self.clean_up()
+
+    def get_platform(self):
+        """ Gets the Platform and Architecture if not supplied """
+
+        if platform.system() == 'Linux':
+            return 'linux'
+
+        elif platform.system() == 'Windows' or 'MSYS_NT' in platform.system():  # Checks for MSYS environment as well
+            return 'windows'
+        else:
+            print('ERROR: Platform not found or supported')
+            sys.exit(0)
+
+    def get_architecture(self):
+        """ Gets the Platform and Architecture if not supplied """
+
+        if '64' in platform.architecture()[0]:
+            return 'x86_64'
+
+        elif '32' in platform.architecture()[0]:
+            return 'x86'
+        else:
+            print('ERROR: Architecture not found or supported')
+            sys.exit(0)
+
+    def download_cores(self, _platform, _architecture):
+        """ Downloads every core to the working directory """
+
+        cores = []
+
+        # Makes core directory to store archives if needed
+        if not os.path.isdir('cores'):
+            os.makedirs("cores")
+
+        # Downloads a list of all the cores available
+        urlretrieve('{}/{}/{}/latest/.index-extended'.format(URL, _platform, _architecture),
+                    'cores/index')
+        self.teditLog.insertPlainText('Obtained core index!')
+
+        # Adds all the core's file names to a list
+        core_index = open('cores/index')
+
+        for line in core_index:
+            file_name = line.split(' ', 2)[2:]
+            cores.append(file_name[0].rstrip())
+        core_index.close()
+        cores.sort()
+
+        # Downloads each core from the list
+        for core in cores:
+            urlretrieve('{}/{}/{}/latest/{}'.format(URL, _platform, _architecture, core),
+                        'cores/{}'.format(core))
+            print('Downloaded {} ...'.format(core))
+
+        # Removes index file for easier extraction
+        os.remove('cores/index')
+
+    def extract_cores(self, _location):
+        """ Extracts each downloaded core to the RA core directory """
+        print('Extracting all cores to: {}'.format(_location))
+
+        for file in os.listdir('cores'):
+            archive = zipfile.ZipFile('cores/{}'.format(file))
+            archive.extractall(_location)
+            print('Extracted {} ...'.format(file))
+
+    def clean_up(self):
+        """ Removes all the downloaded files """
+        if os.listdir('cores'):
+            rmtree('cores/')
 
 
 if __name__ == '__main__':