This Bullet point is 4 pages long, 1 page front cover, 1 page editorial/SRD, leaving us with 2 pages of content, so let's check this out!
The feats herein all modify the fireball-spell like we've already had in some other BP-releases. The feats are:
-Environmental effects: If you cast fireball or other evocation (fire)-effects that affect an area rather than a target, you also create additional effects depending on the area on which the spell goes up, e.g. creating dousing steam clouds that damage creatures immune to fire by casting it in water or creating noxious gases.
-Cometstrike: This feat modifies fireball or similar spells into a comet-like streaking star, changing its area of effect into a line that ends with a smaller explosion. Iconic imagery and tactical option - neat.
-Fiery Wrath: An interesting feat that allows conjured fire elementals or similar creatures at your command to control the burst your fireball produces when caught inside, enabling you to e.g. exclude allies or innocent bystanders from the burst. Neat feat that rewards planning on the player's behalf.
-Implosion: Perhaps not the best name, seeing how there's already a spell called like that, the feat nevertheless is interesting: For an exchange of a bit of blasting capabilities, this feat enables you to modify your fireball to initiate drag maneuvers against those caught within its blast pulling them towards the center of the detonation.
-Shockwave: Essentially the opposite of Implosion, this one enables you to harness the power of your fireballs at the cost of damage to bull rush those caught in the blast.
Editing and formatting are top-notch, I didn't notice any glitches. The layout adheres to SGG'S 3-column standard and the pdf has no bookmarks, but needs none at this length. Fireball is one of the most iconic spells in PFRPG and has been one for more editions than I care to list, thus any modification of it has to be crafted rather carefully and indeed, as could be expected, the pdf delivers some rather neat options to add to this favorite among destructive spells. All of the feats herein are neat and provide some kind of new tactical option beyond what one would expect of simple metamagic. That being said, I still feel like Implosion and Shockwave are rather similar in their mechanics and that the former's name is rather unfortunate. Since all of the feats still can be considered winners and bring something new to the table, I'll nevertheless settle for a final verdict of 5 stars - though I would have loved even more effects for environmental effects or a different implementation, perhaps an own Genius Guide: Misfit Studios' Superior Fantasy Synergy had some (in my opinion) superior ideas there.