I was bored at work the other day and having finished the demo twice, I decided to see how much ag I could mine in the second level (in the demo). I killed off the enemy but before I destroyed the food plant things, I gathered up all the possible ag on the map. I ended up with 144,418 ag
Then I decided to see how many units I could possibly select so I made a whole bunch of the normal marine units. The game came to a slow crawl but persistance payed off. To select all the units I went to the lower-right hand corner and dragged up to the top-left corner... it took 4 min (I timed it) to do that.