I am in Day 5 of Devil Survivor so far, and from what I gather on the GameSpite boards, I'm slightly overleveled. I'm okay with that though! I'm not doing it to break the game, I'm doing it because I'm having fun. I'm sure the game is slightly easier because of this, but oh well - so far, I feel like the difficulty is just right.
I can tell the game is getting tougher quickly, though. The enemies are starting to get some nasty powers such as Holy Dance (Almighty damage dealt randomly to different party members) and Makajamaon (high chance of Mute on all party members). That last one in particular has been giving me some headaches, that's for sure. It can actually turn the tide of a battle fairly quickly!
One of the things I'm guilty of in this game is not having a very large backup demon roster. I usually fuse the guys I want to use, then go into battle. So if one of them dies, and I summon another guy, he is usually level bullshit and gets demolished by a light breeze. I really need to remember to keep a stable of backup demons just in case. I've gotten screwed over a couple times because I forget, too.
One of the things I love about the SMT series is that now that I have played through a few games, when I see a new demon, I have an idea of what it is capable of. For example: I know when I see Thor to expect a badass thunder-wielding physical powerhouse (and I have gone out of my way to make sure I get him in each game)! This has given me a leg-up on some of the battles in Devil Survivor. Since I typically know what strengths and weaknesses certain demons have, battles are somewhat easier because I can exploit them better. The same goes for spell names, too - I knew what Makajamaon was going to do before it hit me that first time.
I just wish I was getting more powerful spells, though. I don't have access to any -dyne spells (the most powerful elemental spells end in -dyne, such as Agidyne, which is fire) yet and my Mazio, Mabufu, Maragi, and Mazan are getting a little weak (all multi-target spells start with Ma-). From what demons I know I'll be unlocking next, one of them has Agidyne - but it's Magic stat is way to low to be useful, really! Oh well. I'll fuse him with some other guys and spread that -dyne around as much as I can.
Storywise, I'm intrigued to see where this goes - supposedly, I have some big decision to make soon. From what I gather, it is basically do I want to: A. Become the King of the World and rule with my badass demons, B. Kill God and eliminate angels and demons from the world, or C. neutralize both angels and demons and banish the real bad guys from the world. Usually I would choose C in games like these because they are The Good Way, but that B looks mighty fine... I've never killed God in a videogame before. I don't mean, like, a God, either. I mean, GOD. Like Yahweh God.
And even if that means I turn into a heartless murderer, it would make for an awesome ending. And there's always New Game +, which will allow me to play through the game again with all the demons I already had unlocked (amongst other things)! So I can easily go get those other endings.