Top stuff, dude! A short & concise, but effective, guide. Can't fault it!
I will just say that the niggly Achievements (Prototype Pilot, Earth Defender, Scourge of the Skurgians, Survivor & Invincible) can be completed Solo on Easy in (pretty much) your first run-through. It also gives you a taster of what you should expect in Normal & Hard difficulties. However, you'll probably get these while going for those harder goals, anyway!
Oh, and mucho congrats for being the official #1 AotG player! ^_^
-=#=- Speed-Run Achievement Walkthroughs -=#=-.