I'm also horribly inconsistent with chains (except for the beginning of level 2, I can usually chain up to when the land runs out on the right side of the screen, but can't figure out how to link to the ships flying in from the left). I know you can get monster-chains on level 5, but I just can't do it.
So I end up playing for "how far can I get" instead of points. I'm pretty damned happy with 2-4.
Also, I have a feeling ZLK is gonna pop in at the last minute with a 20mil score


And I still don't know how you guys get 1mil plus scores on level 1. I can usually get around 800-850k now (but I purposely deplete all my bombs to get more bomb capacity).