Blind Galaxy is one of the older Galaxy varients, dating back to 1992. The engine is based off the Galaxy V2.90 source code (most varients are 3.5x or 3.3 based).
Blind Galaxy, as its name implies, tries to limit your knowledge of the game to what you can observe. Status lines only report those species that you've seen, which often isn't all of them... The tech levels, systems, and fleet sizes represent only what you've encountered this turn.
There are a number of other areas where Blind galaxy differs from its parent. Maps wrap around (i.e. there are no corners). The system mix is different, including size 0 (uninhabitable) worlds and worlds up to twice as large as homeworlds. At systems one owns, war or peace can be selectively set. A foreign power may be set on guard status (only shoot at them over your systems) in addition to the usual war or peace. A number of additional options exist to change the format of one's report, including battle and bombing summaries as well as an option to show what options exist and their settings.
Perhaps the most useful option is the ability to ahve Full reports. These bring all the nearly information for a system into a single section- the system information, groups and fleets there (yours and alien), routes, incoming reports, and a production table showing how much cap/mat/ship mass can be produced.
Blind Galaxy comes with an integrated forecaster which, can either just check one's orders or provide a reasonable approximation of what the next turn report will look like.
Partial techs- building less than the best at a discounted price is supported in Blind Galaxy.
Blind Galaxy reports are not compatible with most tools, due to minor formatting differences as well as extra data from various options. A few tools (or hacks to others) do exist.