Along side being a TSMM expert, I am a BLAB expert as well. I am able to achieve 1,000,000 without stopping since December 2007.
Although there are no annotations in this video, it shows the complete ridethrough of BLAB, along with the high value targets and how to activate the hidden blue triangle in the last room.
YouTube - Buzz Lightyear Astro Blasters
Please note these as you ride the ride:
Once a target is lit and you shoot it. It will REMAIN its lit value until you miss. A crucial key to hit 2,000,000 without stopping.
In the beginning after the "karate chopping" orange robot (it has the blue triangle and purple diamond on BOTH sides of its fists), there is a diamond to your very left. It is not shown in this video.
The first big zurg, the one shooting at you on a pivot point. The green squares on its side. Once you shoot it, it will turn that way, making it easier for you to hit the 50,000 target. It is located in between his two breastplates.
The last zurg, (finale room) also has the 50,000 point target. But, you can only hit it a maximum of three times. During the small turn to the left, that is the ONLY window of opportunity to hit that target.
It is possible to attain 2,000,000 without stopping.