Whoops, I meant Greater Quintessence of Ability Power just to be clear.

You made a mistake on the cheat-sheet in the ability sequence (6 points in Q, 4 points in E), could just be glitch on my end, but worth looking into.

For items, it's an absolute must to get Athene's Unholy Grail first. You can get it pretty early on and still do a ton of damage. Ziggs needs the mana sustain and the CDR to constantly poke the enemy and zone them away from the minions. Besides, you shouldn't rush Rabadon's Deathcap on anyone, because it costs a lot of gold, and only starts to become strong once you have a few AP items. It would be clearer to see item explanations in the actual guide section so consider adding that in.

For match-ups you cover all of them, but you don't say anything about why these types of champions are strong against [[Ziggs] or why he counters other champions.

For runes using Quintessence of Movement Speed is far less effective than running Quintessence of Ability Power. You want the AP rather than the slight extra mobility, for more early game poke as that's what Ziggs excels at.