Massive overhaul

- The project was restarted using Android Studio.
- Adoptive platform-specific widgets has been removed due to build issues with Android.
- Dual-licensed under the BSD-3-Clause license and UNLICENSE.

pubspec.yaml

@@ -1,9 +1,9 @@
 name: bullseye
-description: A game written in Flutter based on a tutorial, with my own tweaks added.
+description: A new Flutter project.
 
 # The following line prevents the package from being accidentally published to
-# pub.dev using `pub publish`. This is preferred for private packages.
-publish_to: "none" # Remove this line if you wish to publish to pub.dev
+# pub.dev using `flutter pub publish`. This is preferred for private packages.
+publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 
 # The following defines the version and build number for your application.
 # A version number is three numbers separated by dots, like 1.2.43
@@ -12,23 +12,31 @@ publish_to: "none" # Remove this line if you wish to publish to pub.dev
 # build by specifying --build-name and --build-number, respectively.
 # In Android, build-name is used as versionName while build-number used as versionCode.
 # Read more about Android versioning at https://developer.android.com/studio/publish/versioning
-# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
+# In iOS, build-name is used as CFBundleShortVersionString while build-number is used as CFBundleVersion.
 # Read more about iOS versioning at
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
+# In Windows, build-name is used as the major, minor, and patch parts
+# of the product and file versions while build-number is used as the build suffix.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: '>=2.18.0 <3.0.0'
 
+# Dependencies specify other packages that your package needs in order to work.
+# To automatically upgrade your package dependencies to the latest versions
+# consider running `flutter pub upgrade --major-versions`. Alternatively,
+# dependencies can be manually updated by changing the version numbers below to
+# the latest version available on pub.dev. To see which dependencies have newer
+# versions available, run `flutter pub outdated`.
 dependencies:
   flutter:
     sdk: flutter
 
+
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^1.0.2
   google_fonts: ^2.1.0
-  flutter_platform_widgets: ^1.9.0
   bitsdojo_window: ^0.1.0+1
   font_awesome: ^5.10.1
 
@@ -36,22 +44,35 @@ dev_dependencies:
   flutter_test:
     sdk: flutter
 
+  # The "flutter_lints" package below contains a set of recommended lints to
+  # encourage good coding practices. The lint set provided by the package is
+  # activated in the `analysis_options.yaml` file located at the root of your
+  # package. See that file for information about deactivating specific lint
+  # rules and activating additional ones.
+  flutter_lints: ^2.0.0
+
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec
 
-# The following section is specific to Flutter.
+# The following section is specific to Flutter packages.
 flutter:
+
   # The following line ensures that the Material Icons font is
   # included with your application, so that you can use the icons in
   # the material Icons class.
   uses-material-design: true
+
   # To add assets to your application, add an assets section, like this:
   # assets:
-  #   - images/
+  #   - images/a_dot_burr.jpeg
+  #   - images/a_dot_ham.jpeg
+
   # An image asset can refer to one or more resolution-specific "variants", see
-  # https://flutter.dev/assets-and-images/#resolution-aware.
+  # https://flutter.dev/assets-and-images/#resolution-aware
+
   # For details regarding adding assets from package dependencies, see
   # https://flutter.dev/assets-and-images/#from-packages
+
   # To add custom fonts to your application, add a fonts section here,
   # in this "flutter" section. Each entry in this list should have a
   # "family" key with the font family name, and a "fonts" key with a