The more I think about it....

[Froge]

The more I start to believe that Alexander is just one giant manchild.

The game attempts to humanize Alexander by telling us that he tortures people in order to return to his world so that he can reunite with his "love" (does it ever mention that this person is his wife? Alexander's sexuality isn't known). The old "love" device is repeatedly apparent in many pieces of literature, film, games, music, art, etc. - basically all of human history. Authors consistently emphasis the painful part of love, which creates some explanation for Alexander's obsessive desire to return to his home world.

However, my own personal experience with love is that, while it can cause crushing sadness, it can't possibly be justification for Alexander's level of douchebaggery. In today's society, you'll of course see teenagers do crazy things for love (e.g. making a fool out of themselves to get their crush's attention). This seems to be the state of mind that Alexander is stuck in. You never really see older people do crazy things for love, and I think it's because they're mature enough to realize that personal love isn't necessarily everything in life, and that sometimes there are more worthwhile things to pursue. Some people, for example, are happy with just platonic love.

Somewhere along the lines of Alexander's torture, he should've realized that other people can love too, and that by kidnapping and killing what one can only presume to be hundreds of innocents, he is destroying the bonds or possible bonds of love that these people also have. Yet the fact that Alexander ignores this makes me believe that he may be psychopathic; his extreme love for his wife or husband, however, suggests that he can, indeed, feel empathy for others. Alexander appears human enough; he should be able to sympathize with other humans. The only possible explanation that I can think of is that he is stuck in a very young state of mind; he'll do anything for love and doesn't care who he hurts to achieve his goal. Therefore, he could just be a very old manchild.