There’s a whole lot of feels here.
Short Version: The Beginner’s Guide is not a game for everyone. It’s not a game for most people. In fact, it is a game for a subset of people who both sympathize with its message and can appreciate its form.
Slightly Longer Short Version: The game starts with a Counterstrike level and the establishment of its narrative form. The narrator, who is also the developer, explains that he’s cobbled together levels made by the programmer Coda and will describe what he likes about each level in the hopes that the resulting publicity will entice Coda back to developing. This serves as the foundation of an extraordinarily personal game about the developer and his need for validation. I’d like to say more, but I really don’t want to ruin it. Instead, I’ll note that, for people who have looked at the world the way the developer has, The Beginner’s Guide is going to grab you. As for me, I never really felt the way the developer did (does?), and so I always felt like a bit of an outsider during this game. This is not a game for me, and it’s may not be a game for you. Fair warning.
As for the rest of the usual bits of game reviewing, they really don’t apply. The graphics are fine, the controls are WADS standard, and the interaction is nothing the player hasn’t seen in The Stanley Parable or other similar walking simulator games. The Beginner’s Guide is, more than any game I’ve played, a vehicle for the narrative. If you’re on board with it, I’m sure it’s a touching experience. For everyone else, your appreciation of this game diminishes proportionally to how much the message and form means to you.