I understimated the complexity of my project, and overstimated the resources of Spectrum BASIC :-). Although I've tried to stay low on features, I've had problems in terms of optimizing BASIC code. I've forgotten how low on resources the Spectrum was.
Fitting 8 galaxies with over 200 diferent planets per galaxy is a complex task on such low resources. Also trying to make the gameplay cool giving a sense of freedom to the player, letting him to move between planets (and galaxies), trade and fight and, at the same time, maintain a not so ugly visual aspect is complicated on the limits that ZX BASIC imposes.
In fact, I've been the last two nights thinking on how to optimize the damn keyboard input. To make it as responsive as can be in a BASIC game.
That said, I think I can finish it near the time limit. Ah! and hope not to break the 500 lines limit imposed! OMG!!! o_o