Stage	Definition of the milestone
Final Concept	Fully fleshed out designs for all major features have been created in order to guide the full development of the game. This is the foundational creative information that the team will be using to engage in full development of the game's vision. The planned game-loop is outlined in documentation with enough detail to direct development and communicate what the player interactions are intended to be. All technologies, the story arc, etc are defined and proofed.- All general risks were defined and written down into the project risk register.
Prototype	A build encompassing basic functionality for the major planned features as a proof of concept and very early look at the feasibility of the tech/features/visuals being built. This should also help prove out the moment-to-moment player experience as outlined in the design documentation. Alternatively, the prototype may illuminate flaws in the design and inform design shifts/changes.
First Playable / Gameplay Validation	At this stage, builds can be created which are able to prove out a first look at the basic core gameplay loop. This is the first basic playable build of a section of the game which will inform the core "fun" of the game. Not every system needs to be in place, but the core loop needs to be intact enough so that it can be played, understood and evaluated (debug is still ok to use). Minute - to minute gameplay should be evident as well as an obvious example of the meta game/progression (what makes the player continue playing and coming back)
Vertical Slice	Features and content in one level of the game are generally functioning together with representative art (not final, but shows intended art direction; not blockout), so that the core game loop can be assessed for one full area of the game. The assessment can then be extrapolated to the other portions of the game, with the mindset that a vast majority of the remainder of development lies in content creation. Spiritually similar to 'vertical chunk' but on a smaller scale.
Vertical Chunk / Final Spec	A check-in during production to ensure that all expectations are concretely aligned on the mission of the project — especially in cases where design vision may have evolved. Features are largely functional, and no longer require debug to use, save for a few exceptions. All major features are proven out and can be reviewed in concert with one another to ascertain if any other minor supporting features will be required for the product.
Feature Complete	All features are proven and fully functional (bugs notwithstanding). The build is ready for full feature testing through QA. Debug is no longer necessary to functionally test any aspect of the game, but may still be used to bypass bugs.
Alpha	The game's content is now in the build, and the game can be played from beginning to end without major blockers or crashes. This is a point in time for last passes at content review and feedback, which can be captured in the polish phases. Much of the team is shifting to bug fixing at this point.
Beta	The Game has all content integrated at shippable quality and all features are fully playable. Active content creation has concluded, and only functional bugs are being addressed at this point. Content changes/fixes have concluded in order to prioritize stability — Launch-blocking issues notwithstanding.
RC1	The game has reached a finalized state where no further submission blockers remain, and a release candidate has been designated by QA.
Final Build	The released build and any applicable Day 0/Day 1 patches are archived and sent through the copyright process.