I've compiled a short guide on Breakthrough, you can find it here (7 pages, 12 problems). There are some other guides, you can find them on my LG profile. This one is really a slightly modified version of Carlos' article on BGG (many thanks!). If you have any comments to make, I'll appreciate that very much! Besides mistakes or unclarities I am particularly interested in additional heuristics and problems, especially harder ones.
I've realised too late this very forum has a good discussion about first player advantage. Please ignore the question in the text about this, unless new information is available. I will incorporate that thread.
