There is no option to bombard systems in the game yet. There is no combat system either and no AI - so the game is easy because you're not actually playing against anyone!
The combat system is being done by CdrWolfe, who said he will start working on it again sometime soon now that he's got some free time, and Mike said he will add the bombard system option as part of a future update. The AI will be added as part of a future update as well, but that's much, much further down the line as it is likely to be the single most complex bit of programming that Mike will have to write.
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