The 10.1 repositories have xgalaga (Galaga clones, don't know if that's close enough for your tastes, and pls forgive me if the very idea offends ). Glaxium is kind of a 3D version of that genre. There's something called lwjgl-demo that I don't have installed that purports to have a Space Invaders clone included in it.

Not in the repositories, but Softpedia has "RetroVaders", which says it's a tribute to Space Invaders, and screenshots look right.