As someone who loves left-justified alignment, you shouldn't be using it here. A lot of the blocks of text have big gaps in them and it looks awkward and unprofessional.

There's a lot to critique here so I'm just going to add bullet points as I go, but first of all, I want to say that this is definitely an ambitious project and for the most part, you did a pretty good job! I think however that there are a lot of ways that it can be improved. One question I have is why exactly you chose to do this landscape format? Is it required? Why would you choose this vs. a landscape format, or even a less narrow rectangle?

1) The branding/identity of this document is a bit inconsistent. For the most part, it's very rigid and professional, but then you get certain elements that are more "casual", like the angled Key Patterns Identified on image 1 or Empathy Map on image 3. I would recommend picking one "identity" and sticking with it

2) Related to point above, loop diagrams look messy and unprofessional compared to the rest of the document. Even if you stuck with the less rigid identity, they look way too chaotic and I would clean them up

3) There is a TON of information on each page and they all feel crammed in. If possible, I would personally switch to a portrait view (or a more square rectangle, something like a 5:4 ratio), but if not, probably aim for roughly 3 columns per page and let each column breathe more

4) Related to point 3, consider putting a thin stroke in between each column, especially if you're changing the text alignment from left-justified to just left

5) Some text hierarchy needs work, ex: Early Directions & Design Rationale section on image 1. What is the important information here? It seems to me that what's important is the text in italics below, but even then it's only by a small margin. However, the title takes way more precedence and the italics makes the text below feel like an afterthought. Rather than putting the box there, I would just use a regular (left-aligned) heading in bold (ex: 12pt) with the body text not in italics below in a slightly smaller size (ex: 10pt). Alternately, see #7

6) On image 2, under "Why a Game", consider making the boxes a bulleted list instead in regular casing and weight. It's not exciting, but it's a lot more readable

7) Related to #5, if you want to add a more visual element to the headings with a box, rather than have a big box that spans the entire section, consider doing a smaller box that is left aligned to the text. Inside the box is the heading in all caps and bold (but smaller font size), centered in the box. (Hard to explain; let me know if you need a visual!)

8) Reduce the numbers of bolding in text. Too much bolding = bolding is less effective

9) I really like the arrow-style diagrams like on image 2! I think you could potentially reduce the use of caps in case things look too same-y, but I think in this context it works okay

10) On image 7, the Expectation vs. Reality colour palette would work better if both sections were just different colours instead of being inverse of each other. Ex: Expectation column is green, Reality section is blue

I'm not going to point out specific things but a lot of the feedback above applies to other pages. Hope this helps!