The way one writes anything, including guides, and sell same for profit without legal issues relating to copyright infringement is to avoid using another person's material.
If one is going to use the material of another in one’s work, one must either: (a) obtain permission/license or (b) use no more of the other person’s work than the “FAIR USE” allows.
In the Kopps v Blizzard example you cited, Kopps apparently only use a few “screen shots” of the Wizard and Warcraft game. If such is true, it is very likely such use falls under fair use.
Thus, while this case was settled out of court, Kopp would almost surely have won.
However, Kopp was stilled sued.
The point is, even if you do everything right, you can still be sued by companies that wish to drive you out of business whether you are right or not. Such is often called copyfraud.
They have the deep pockets and they believe individuals will simply stop selling the guide rather than fight a legal battle.
Such cannot be avoided but one can do everything possible to have as strong a legal position as possible.
Thus, we need to review some basic DMCA and Copyright Law and then consider what you need to do.
Now many companies use and abuse the DMCA take down request to attack individuals selling something the company does not like.
Below is the relevant DMCA provision
DMCA : 17 U.S.C. § 512(c)(3)(A)
The DMCA requires that copyright owners provide the following information in a takedown notice:
(i) A physical or electronic signature of a person authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.
(ii) Identification of the copyrighted work claimed to have been infringed, or, if multiple copyrighted works at a single online site are covered by a single notification, a representative list of such works at that site.
(iii) Identification of the material that is claimed to be infringing or to be the subject of infringing activity and that is to be removed or access to which is to be disabled, and information reasonably sufficient to permit the service provider to locate the material.
(iv) Information reasonably sufficient to permit the service provider to contact the complaining party, such as an address, telephone number, and, if available, an electronic mail address at which the complaining party may be contacted.
(v) A statement that the complaining party has a good faith belief that use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.
(vi) A statement that the information in the notification is accurate, and under penalty of perjury, that the complaining party is authorized to act on behalf of the owner of an exclusive right that is allegedly infringed. 17 U.S.C. § 512(c)(3)(A) (emphasis added).
NOW, note (v) above requires a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.
OK. While Congress did not expressly mention the FAIR USE DOCTRINE in the DMCA, the Copyright Act provides explicitly that “the fair use of a copyrighted work . . . is not an infringement of copyright.” 17 U.S.C. § 107.
Accordingly, in order for a copyright owner to proceed under the DMCA with “a good faith belief that use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law,” the owner must evaluate whether the material makes fair use of the copyright. 17 U.S.C. § 512(c)(3)(A)(v).
Such is basically what Kopp argued.
Further Note this:
An allegation that a copyright owner acted in bad faith by issuing a takedown notice without proper consideration of the fair use doctrine is sufficient to state a misrepresentation claim pursuant to Section 512(f) of the DMCA.
Kopp based one of his causes of action on 512(f) for the very reason indicated above.
So now we need to consider the concept of FAIR USE
The Copyright Act of 1976, 17 U.S.C. § 107, sets forth four, non-exclusive factors that a court must consider in determining whether a particular use of a copyrighted work is a fair use.
[T]he fair use of a copyrighted work . . . for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include--
(1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
(2) the nature of the copyrighted work;
(3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
(4) the effect of the use upon the potential market for or value of the copyrighted work.
HOW TO EVALUATE THE FACTORS
(1) Purpose and Character of Use
The first factor is the “heart of the fair use inquiry” and requires consideration of how the copied work was used. Cariou v. Prince, 714 F.3d 694, 705 (2 Cir. 2013) (citing Blanch v. Koons, 467 F.3d 244, 251 (2 Cir. 2006)).
Although the copyright act instructs courts to look at the commercial nature of the use, the Supreme Court has made clear that commercial uses are not presumptively unfair. Campbell v. Acuff–Rose Music, Inc., 510 U.S. 569, 584 (1994) (finding Congress “could not have intended” such a blanket rule).
As the Court has explained, “[t]he crux of the profit/nonprofit distinction is not whether the sole motive of the use is monetary gain but whether the user stands to profit from exploitation of the copyrighted material without paying the customary price.” Harper & Row, 471 U.S. at 562; see also Am. Geophysical Union v. Texaco Inc., 60 F.3d 913, 922 (2 Cir. 1994) (“The commercial/ nonprofit dichotomy concerns the unfairness that arises when a secondary user makes unauthorized use of copyrighted material to capture significant revenues as a direct consequence of copying the original work.”).
As a result, the crucial inquiry in the first factor is “whether the new work merely supersedes the original work, or instead adds something new with a further purpose or of a different character.” Brownmark, 682 F.3d at 693 (citing Campbell, 510 U.S. at 579, which defines a transformative work as one that “adds something new, with a further purpose or different character, altering the first with new expression, meaning or message”). The Court observed that, “the more transformative the new work, the less will be the significance of other factors, like commercialism, that may weigh against a finding of fair use.” Campbell, 510 U.S. at 579.
(2) Nature of The Copyrighted Work
Courts generally consider two aspects of a copyrighted work in evaluating this factor:
(1) whether the work is more creative or factual in nature, and
(2) whether it is unpublished, in which case the right of first publication is implicated. Núñez v. Caribbean Intern. News Corp., 235 F.3d 18, 23 (1 Cir. 2000) (citing Harper & Row, 471 U.S. at 563-64). “
“[T]he more creative the work, the more protection it should be accorded from copying; correlatively, the more informational or functional the plaintiff’s work, the broader should be the scope of the fair use defense.”
For example, a video of a presidential assassination would get thin copyright protection as such video is informational of great public importance.
With respect to the second aspect of the second factor, such aspect relates to the right of first publication.
In one case,the court noted that defendants’ use of Kienitz’s photograph did not usurp his right of first publication. Although the photograph never had been published in any book or public portfolio, it appears on the City of Madison website, on Mayor Soglin’s internet blog and on his Facebook page. Kienitz intended for Mayor Soglin to use the photograph publically as an official portrait and for any other non-commercial use. Núñez, 235 F.3d at 24 (noting pictures commissioned for very purpose of semi-public dissemination).
With relevant considerations pointing both directions, I do not find that the factor addressing the nature of the work strongly favors either side. Therefore, I have attributed it little weight in the fair use analysis.
(3) Amount and Substantiality of Work Used
The third factor requires a court to examine the amount and substantiality of what was used in relation to the copyrighted work as a whole. Harper & Row, 471 U.S. at 564. It is both a qualitative and quantitative analysis. Campbell, 510 U.S. at 586; Bill Graham Archives v. Dorling Kindersley Ltd., 448 F.3d 605, 613 (2 Cir. 2006).
There is no per se rule against copying a work as a whole if it is necessary to the purpose and character of the use. Chicago Bd. of Educ., 354 F.3d at 629. The focus is not on how much of the work was taken but to what extent the protected elements were copied from the original. See Salinger v. Random House, Inc., 811 F.2d 90, 97 (2 Cir. 1987); 1 Art, Artifact, Architecture and Museum Law § 7.109.
Example: Thumbnail Images
See Bill Graham Archives, 448 F.3d at 613 (although thumbnail images of concert posters used entire copyrighted images, “the visual impact of their artistic expression is significantly limited because of their reduced size”).
In sum, this factor weighs in favor of fair use because the amount and substantiality of the photograph used by defendants was “reasonable in relation to the purpose of the copying.” Campbell, 510 U.S. at 587-88; see also Blanch, 467 F.3d at 258 (finding reasonable defendant’s choice to extract portions of copyrighted work with purpose of evoking “certain style of mass communication”).
(4) Effect of Defendants’ Use on the Market
The Supreme Court has stated that this factor is “the single most important element of fair use.” Harper & Row, 471 U.S. at 566.
“Fair use, when properly applied, is limited to copying by others which does not materially impair the marketability of the work which is copied.” Id. at 566-67, quoting 1 Nimmer, § 1.10[D] at 1-87; see also Stewart v. Abend, 495 U.S. 207, 238 (1990).
The question is whether the new work will be a market substitute for the copyrighted material. Campbell, 510 U.S. at 591.
A court must consider “not only the extent of the market harm caused by the particular actions of the alleged infringer, but also ‘whether unrestricted and widespread conduct of the sort engaged in by the defendant . . . would result in a substantially adverse impact on the potential market’” for the original. Id. at 590 (quoting 3 Nimmer § 13.05[A], at 13–102.61). “The less adverse impact on the owner, the less public benefit need be shown to sustain non-commercial fair use.” Rogers, 960 F.2d at 311-12.
If the new work substitutes for and is likely to reduce the demand for the copyrighted original, then it is not a fair use. Ty, Inc. v. Publications International Ltd., 292 F.3d 512, 518 (7 Cir. 2002)
Thus, you guide should not use material from another, however, since it is a guide it probably uses "screen shots" and similar material to make explaining issues easier to understand.
What you need to do is make sure such use falls under "Fair Use" as defined above OR obtain permission/license from the copyright owner.
The only absolute safe way is to obtain a license/permission to use the material whether or not such license/permission is required. But such is unnecessary if one's use of another's material falls under FAIR USE.
(1) Purpose and Character of Use
This factor is probably neutral for your gaming guide. There work has already been published and your work does not unfairly attempt to profit off of the games good will. You simply created a new work.
(2) Nature of Work
This factor probably neutral.
(3) Amount and Substantiality of Work Used
If you use the material of others in your "game guide", and such materials are simply "screen shots", just enough to make your point, then the odds are great that such use will be considered de minimis and falls under FAIR USE.
(4) Effect of Defendants’ Use on the Market
If anything, you gaming guide could increase the sales of their game. The factor likely falls in your favor.