he forgot many things:

ODSTs, Spartans(all classes), prowlers, that covenant ships use plasma which burns through armor and sheilds, forgot the names for drones, engineers, High Charity, how fast flood reproduce, Sentinels, Sentinel Majors and Enforecersand how many types of nukes the UNSC has... many many things

I didn't forget those things. I pointed out that ODST (Helljumpers) would not stand a chance against Terran Marine Corps. ODST's are little more than slightly better trained UNSC marines in light armored space suits. I also pointed out that Master Chief would mix up the battle, but he couldn't take on the entire Starcraft world. As for the rest of the spartans... theres like 3 left? The kiddie spartans would be a comparable fight for a Terran Ghost.

Covenant plasma weapons burn armor but they don't make a clean burn. If they did, the UNSC would have an even harder time than they currently do fighting. Besides, its kind of hard to hit a cloaked vessel.

Engineers = Terran SCVs. Zerg produce just as fast as Flood, if not faster. Both sides have nukes and lots of them. I purposefully left out the Sentinels because they seldom leave Halo, and therefore would be about as effective as the Terminators stuck on Earth. The bottom line remains: every Starcraft matchup ends in a draw or a victory for Starcraft.