Biggest game changes are:
-Scoring 15000 and 50000 points now gives an extra shield. Maximum shield amount is now five.
-It is possible to fire the laser in the warp tunnel.
-The sights are more effective for aiming. The targets in the motherships are also slightly larger.
-The enemy rockets can be either shot down or dodged. However, an enemy shield generator can protect the rockets too...
-Nothing is protected from your missiles, so try to collect the missiles before attempting to take over the enemy motherships. They are pretty handy for countering the incoming rockets.
-Often it's not useful to travel the thick asteroid fields. It's only necessary in very few scenarios.
-Collecting the cards itself does not score. A poor hand can give less points than collecting four normal cargo!
-For expert players: Killing the waves rapidly gives an exponentially increasing bonus. Exploit this in asteroid fields, which are double-score zones. Failing to kill a wave rapidly resets the bonus. Missiles make this a lot simpler!
-Drumming the laser with fingers gives more rapid fire than holding down your finger.