I’m not familiar with the older brothers, the main parts of the series, and I would hardly have gotten acquainted with this game if it had not been bundled with the PSP itself. The relationship was good, I went from beginning to end, and destroyed the aliens to my heart's content (they were the ones I remember most, with their characteristic eyes and fangs; it seems they have become quite recognizable). And we can say with confidence that, for a portable Sonya, the game is really cool. I remember well that the controls were convenient and the gameplay was quite entertaining.
What surprised me was that the game was developed by the same studio that would later screw up Golden Abyss in the Uncharted line. They can, after all. Although a lot of water could have flowed under the bridge since then...