The document introduces Unity's native 2D tools, including 2D editor mode, importing textures as sprites, sorting layers, 2D physics and colliders, sprite slicing, the animator system for sprite and skeleton-style animation, and the sprite packer. It also discusses Unity's support for 2D game development through plugins, the 4.3 update, examples like Hearthstone and Teslagrad, and UI systems like uGUI. The introduction covers collisions and triggers as well as rounding up the key 2D features before concluding with a thank you and invitation for questions.