Spoilers for SMT1 & 2, I guess. Avoid the post if you're a stickler for story stuff.
Himuro said:
What I like is that it doesn't shove it in your face like with the Xeno games. But that can't be said about the earlier games apparently..
The older games in the main Megaten series (Shin Megami Tensei 1, Shin Megami Tensei 2) did not "shove [religion] in your face," but they did include figures from assorted religions who played a much bigger role in the overall story (in comparison to SMT3 and the DDS games). Two of the most prominent individuals were YHVH and Lucifer from the Judeo-Christian beliefs. YHVH was not depicted in the best of lights; he came off as a cold and merciless entity that demanded order and submission from his followers, willingly bringing about worldwide nuclear holocaust and flooding the world in order to wipe out the non-believers. Lucifer was shown to be a freedom fighter-ish figure who promoted free will, yet his ideals would've lead to a world where the strong dominated the weak.
So in the first two games, you could make decisions that would shift your alignment towards Law (YHVH) or Chaos (Lucifer). There was also a third path, that of neutrality, but this path was the bloodiest and most challenging in both games, not just because you'd have to try and balance your alignment so that it didn't dip too far on either end, but you would also have to fight people on both sides (normally, if you fully aligned yourself with one side, you'd avoid a couple of boss fights). SMT1 & 2 are still my favourite RPGs, and despite 3 being an excellent game, its removal of some key aspects of the Megaten series still irks me. I did appreciate the new role for Lucifer though.
The Devil Summoner games are a lot closer to SMT1 & 2 than the Persona series. They basically retain the key aspects of the main series (1st person perspective, Magnetite usage, a female partner who uses magic, Hero wielding a melee weapon & a gun), but their stories are less apocalyptic (at least initially), and the human characters are given more personality and exposure. The demon conversations and negotiations aspect were greatly enhanced in both Devil Summoner & Soul Hackers (much to the horror of fans who don't read enough Japanese), but the addition of the [broken] loyalty system pretty much ruined Devil Summoner. Thankfully, its reappearance in Soul Hackers was completely retooled and made much more manageable. Soul Hackers also introduced the fan favourite Nemissa, although I'm still partial to Reireiho from DS.
If we have any more Megaten fans around here who could go into more details about the games or have corrections about anything I've said (or would like to debate Chaos vs Law vs Neutral), please chime in. I'm far from being an expert on these games.