diff --git a/installer.lua b/installer.lua
index d009d42..e4080d9 100644
--- a/installer.lua
+++ b/installer.lua
@@ -1,95 +1,448 @@
-install = {
-  title = 'Opus OS',
-  version = '1.0',
-  author = 'Kepler',
+--[[
+  Opus OS Installer
+  Self-contained installer that downloads from Gitea
+]]
 
-  description = [[
-A user friendly operating system featuring multitasking, networking,
-and automation
-]],
+local GITEA_HOST  = 'git.spatulaa.com'
+local GITEA_USER  = 'MayaTheShy'
+local GITEA_REPO  = 'Opus'
+local GITEA_BRANCH = 'main'
 
-  license = [[
-Permission is hereby granted, free of charge,
-to any person obtaining a copy of this software and associated documentation
-files (the "Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish, distribute,
-sublicense, and/or sell copies of the Software, and to permit persons to whom the
-Software is furnished to do so, subject to the following conditions:
+local TREE_URL = 'https://%s/api/v1/repos/%s/%s/git/trees/%s?recursive=1'
+local FILE_URL = 'https://%s/%s/%s/raw/branch/%s/%s'
 
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
+local colors    = _G.colors
+local fs        = _G.fs
+local http      = _G.http
+local os        = _G.os
+local parallel  = _G.parallel
+local term      = _G.term
+local textutils = _G.textutils
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
-IN THE SOFTWARE.]],
+local args = { ... }
+local mode = args[1] or 'install'
 
-  copyrightYear = 2018,
-  copyrightHolders = 'Kepler',
+-- Utility functions
 
-  diskspace = 380000,
-  rebootAfter = true,
-  gitRepo = 'kepler155c/opus',
+local function httpGet(url)
+  local h, msg = http.get(url)
+  if h then
+    local content = h.readAll()
+    h.close()
+    return content
+  end
+  return nil, msg
+end
 
-  gitBranch = 'main',
-  branches = {
-    { branch = 'main',          description = 'Main'          },
-    { branch = 'develop-1.8',   description = '1.8+ Unstable' },
-    { branch = 'master-1.8',    description = '1.8+ Stable'   },
-    { branch = 'master',        description = '1.7x Stable'   },
-    { branch = 'develop',       description = '1.7x Unstable' },
-  },
+local function download(url, path)
+  local dir = fs.getDir(path)
+  if dir ~= '' and not fs.exists(dir) then
+    fs.makeDir(dir)
+  end
+  local content, msg = httpGet(url)
+  if content then
+    local f = fs.open(path, 'w')
+    f.write(content)
+    f.close()
+    return true
+  end
+  return false, msg or 'Download failed'
+end
 
-  preCopy = function(mode)
-    if mode == 'update' then
-      fs.delete('sys')
+local function formatSize(size)
+  if size >= 1000000 then
+    return string.format('%dM', math.floor(size / 1000000))
+  elseif size >= 1000 then
+    return string.format('%dK', math.floor(size / 1000))
+  end
+  return tostring(size)
+end
+
+local function center(text, y)
+  local w = term.getSize()
+  term.setCursorPos(math.floor((w - #text) / 2) + 1, y)
+  term.write(text)
+end
+
+local function drawHeader(title)
+  local w = term.getSize()
+  term.setBackgroundColor(colors.cyan)
+  term.setTextColor(colors.white)
+  term.setCursorPos(1, 1)
+  term.clearLine()
+  center(title, 1)
+  term.setBackgroundColor(colors.black)
+  term.setTextColor(colors.white)
+end
+
+local function drawProgressBar(y, pct)
+  local w = term.getSize()
+  local barW = w - 4
+  local filled = math.floor(barW * pct / 100)
+
+  term.setCursorPos(3, y)
+  term.setBackgroundColor(colors.gray)
+  term.write(string.rep(' ', barW))
+  term.setCursorPos(3, y)
+  term.setBackgroundColor(colors.lime)
+  term.write(string.rep(' ', filled))
+  term.setBackgroundColor(colors.black)
+end
+
+local function waitForKey(prompt)
+  local _, h = term.getSize()
+  if prompt then
+    term.setTextColor(colors.lightGray)
+    center(prompt, h)
+  end
+  os.pullEvent('key')
+end
+
+-- Get file listing from Gitea API
+
+local function getFileList(branch)
+  local url = string.format(TREE_URL, GITEA_HOST, GITEA_USER, GITEA_REPO, branch)
+  local content, msg = httpGet(url)
+  if not content then
+    return nil, 'Failed to get file list: ' .. (msg or 'unknown error')
+  end
+
+  local data = textutils.unserialiseJSON(content)
+  if not data then
+    return nil, 'Invalid response from server'
+  end
+  if data.message then
+    return nil, data.message
+  end
+
+  local files = {}
+  local totalSize = 0
+  for _, v in pairs(data.tree) do
+    if v.type == 'blob' then
+      local path = v.path:gsub('%s', '%%20')
+      files[path] = {
+        url = string.format(FILE_URL, GITEA_HOST, GITEA_USER, GITEA_REPO, branch, path),
+        size = v.size or 0,
+      }
+      totalSize = totalSize + math.max(500, v.size or 0)
     end
-  end,
+  end
 
-  steps = {
-    install = {
-      'splash',
-      'license',
-      'branch',
-      'files',
-      'review',
-      'install',
-    },
-    update = {
-      'branch',
-      'review',
-      'install',
-    },
-    automatic = {
-      'install',
-    },
-    uninstall = {
-      'review',
-      'uninstall',
-    },
-  },
-}
-
-print('Downloading Installer...')
-
-local url = 'https://raw.githubusercontent.com/kepler155c/opus-installer/master/sys/apps/Installer.lua'
-local h = _G.http.get(url)
-if not h then
-  error('Failed to download installer')
+  return files, nil, totalSize
 end
 
-local contents = h.readAll()
-if not contents then
-  error('Failed to download installer')
+-- Splash screen
+
+local function showSplash()
+  term.clear()
+  drawHeader('Opus OS Installer')
+
+  local _, h = term.getSize()
+  local y = 3
+
+  term.setTextColor(colors.yellow)
+  center('Opus OS v1.0', y)
+  y = y + 2
+
+  term.setTextColor(colors.white)
+  center('By: Kepler', y)
+  y = y + 2
+
+  term.setTextColor(colors.lightGray)
+  local desc = {
+    'A user friendly operating system',
+    'featuring multitasking, networking,',
+    'and automation.',
+  }
+  for _, line in ipairs(desc) do
+    center(line, y)
+    y = y + 1
+  end
+
+  y = y + 1
+  term.setTextColor(colors.gray)
+  center('Source: ' .. GITEA_HOST, y)
+
+  waitForKey('Press any key to continue...')
 end
 
-local fn, msg = load(contents, 'Installer.lua', nil, _ENV)
-if not fn then
-  _G.printError(msg)
-else
-  local args = { ... }
-  fn(args[1])
+-- License screen
+
+local function showLicense()
+  term.clear()
+  drawHeader('License Review')
+
+  local _, h = term.getSize()
+  term.setCursorPos(2, 3)
+  term.setTextColor(colors.yellow)
+  print('  Copyright (c) 2018 Kepler')
+  print()
+  term.setTextColor(colors.lightGray)
+
+  local license = [[
+  Permission is hereby granted, free of
+  charge, to any person obtaining a copy
+  of this software to deal in the Software
+  without restriction, including without
+  limitation the rights to use, copy,
+  modify, merge, publish, distribute,
+  sublicense, and/or sell copies of the
+  Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS",
+  WITHOUT WARRANTY OF ANY KIND.]]
+
+  print(license)
+
+  waitForKey('Press any key to accept...')
 end
+
+-- Branch selection (only shown for full install)
+
+local function selectBranch()
+  local branches = {
+    { branch = 'main',        description = 'Main (Stable)' },
+    { branch = 'develop-1.8', description = '1.8+ Unstable' },
+    { branch = 'master-1.8',  description = '1.8+ Stable'   },
+  }
+
+  local selected = 1
+
+  while true do
+    term.clear()
+    drawHeader('Select Branch')
+
+    local _, h = term.getSize()
+    term.setCursorPos(2, 3)
+    term.setTextColor(colors.yellow)
+    print('  Choose which branch to install:')
+    print()
+
+    for i, b in ipairs(branches) do
+      term.setCursorPos(3, 4 + i)
+      if i == selected then
+        term.setTextColor(colors.yellow)
+        term.write('> ')
+      else
+        term.setTextColor(colors.white)
+        term.write('  ')
+      end
+      term.write(b.branch)
+      term.setTextColor(colors.gray)
+      term.write(' - ' .. b.description)
+    end
+
+    term.setTextColor(colors.lightGray)
+    center('Up/Down to select, Enter to confirm', h)
+
+    local event, key = os.pullEvent('key')
+    if key == keys.up then
+      selected = selected > 1 and selected - 1 or #branches
+    elseif key == keys.down then
+      selected = selected < #branches and selected + 1 or 1
+    elseif key == keys.enter then
+      return branches[selected].branch
+    end
+  end
+end
+
+-- File list review
+
+local function showFileReview(files, totalSize)
+  term.clear()
+  drawHeader('Review Files')
+
+  local _, h = term.getSize()
+  local count = 0
+  for _ in pairs(files) do count = count + 1 end
+
+  term.setCursorPos(2, 3)
+  term.setTextColor(colors.yellow)
+  print(string.format('  %d files to install', count))
+  print()
+  term.setTextColor(colors.white)
+  print(string.format('  Space required: %s', formatSize(totalSize)))
+
+  local diskFree = fs.getFreeSpace('/')
+  if totalSize > diskFree then
+    term.setTextColor(colors.red)
+    print(string.format('  Free space:     %s  (NOT ENOUGH!)', formatSize(diskFree)))
+  else
+    term.setTextColor(colors.lime)
+    print(string.format('  Free space:     %s', formatSize(diskFree)))
+  end
+
+  print()
+  term.setTextColor(colors.lightGray)
+
+  -- Show first few files
+  local shown = 0
+  for path in pairs(files) do
+    if shown < (h - 11) then
+      term.setCursorPos(3, 9 + shown)
+      local display = path
+      local w = term.getSize()
+      if #display > w - 4 then
+        display = '...' .. display:sub(-(w - 7))
+      end
+      term.write(display)
+      shown = shown + 1
+    end
+  end
+  if count > shown then
+    term.setCursorPos(3, 9 + shown)
+    term.setTextColor(colors.gray)
+    term.write(string.format('... and %d more files', count - shown))
+  end
+
+  waitForKey('Press any key to begin install...')
+end
+
+-- Install files with progress
+
+local function installFiles(files)
+  if mode == 'update' then
+    fs.delete('sys')
+  end
+
+  term.clear()
+  drawHeader('Installing...')
+
+  local _, h = term.getSize()
+  local total = 0
+  for _ in pairs(files) do total = total + 1 end
+
+  local fileList = {}
+  for path, entry in pairs(files) do
+    table.insert(fileList, { path = path, url = entry.url })
+  end
+
+  local completed = 0
+  local failed = 0
+  local lastFile = ''
+
+  -- Download with 5 parallel workers
+  local workers = {}
+  for _ = 1, 5 do
+    table.insert(workers, function()
+      while true do
+        local entry = table.remove(fileList)
+        if not entry then break end
+
+        lastFile = entry.path
+        local s, m = download(entry.url, entry.path)
+        if not s then
+          failed = failed + 1
+        end
+        completed = completed + 1
+      end
+    end)
+  end
+
+  -- Progress display alongside downloads
+  table.insert(workers, function()
+    while completed < total do
+      local pct = math.floor(completed / total * 100)
+
+      term.setCursorPos(2, 4)
+      term.setTextColor(colors.white)
+      term.clearLine()
+      term.write(string.format(' Progress: %d/%d (%d%%)', completed, total, pct))
+
+      term.setCursorPos(2, 6)
+      term.setTextColor(colors.lightGray)
+      term.clearLine()
+      local w = term.getSize()
+      local display = lastFile
+      if #display > w - 4 then
+        display = '...' .. display:sub(-(w - 7))
+      end
+      term.write(' ' .. display)
+
+      drawProgressBar(h - 3, pct)
+
+      if failed > 0 then
+        term.setCursorPos(2, 8)
+        term.setTextColor(colors.red)
+        term.write(string.format(' Failed: %d', failed))
+      end
+
+      os.sleep(0.1)
+    end
+  end)
+
+  parallel.waitForAll(table.unpack(workers))
+
+  -- Final progress update
+  drawProgressBar(h - 3, 100)
+  term.setCursorPos(2, 4)
+  term.setTextColor(colors.lime)
+  term.clearLine()
+  term.write(string.format(' Complete: %d/%d files', completed, total))
+
+  term.setCursorPos(2, 6)
+  term.clearLine()
+
+  if failed > 0 then
+    term.setCursorPos(2, 8)
+    term.setTextColor(colors.red)
+    term.write(string.format(' %d files failed to download', failed))
+  end
+
+  return failed == 0
+end
+
+-- Done screen
+
+local function showDone(success)
+  local _, h = term.getSize()
+
+  term.setCursorPos(2, h - 1)
+  if success then
+    term.setTextColor(colors.yellow)
+    center('Install complete! Rebooting...', h - 1)
+    os.sleep(2)
+    os.reboot()
+  else
+    term.setTextColor(colors.red)
+    center('Install finished with errors.', h - 1)
+    waitForKey('Press any key to exit...')
+  end
+end
+
+-- Main installer flow
+
+local function main()
+  local branch = GITEA_BRANCH
+
+  if mode == 'install' then
+    showSplash()
+    showLicense()
+    branch = selectBranch()
+  end
+
+  -- Get file list
+  term.clear()
+  drawHeader('Opus OS Installer')
+  term.setCursorPos(2, 4)
+  term.setTextColor(colors.white)
+  term.write(' Fetching file list...')
+
+  local files, err, totalSize = getFileList(branch)
+  if not files then
+    term.setCursorPos(2, 6)
+    term.setTextColor(colors.red)
+    print(' Error: ' .. (err or 'unknown'))
+    waitForKey('Press any key to exit...')
+    return
+  end
+
+  if mode == 'install' then
+    showFileReview(files, totalSize)
+  end
+
+  local success = installFiles(files)
+  showDone(success)
+end
+
+main()