Well, by older games, I'm going to assume you mean main series games prior to Nocturne/Lucifer's Call, so... Megami Tensei: I've played both versions and the Kyūyaku Megami Tensei version is by far the better of the two. The NES original has a lot of first-installment quirks that get annoying fast (no Auto-Map, you can only negotiate with a demon if it's alone, don't have any way to know demon Levels without a guide, etc.). The Kyūyaku Megami Tensei version is a more or less full remake that plays a lot more like Megami Tensei II with other amenities from later games (such as Auto-Map) added in as well. Megami Tensei II: Again, played both versions, but I think the Kyūyaku Megami Tensei version is better. The NES version of this game is very tough, possibly even more than Nocturne and Strange Journey. The Kyūyaku Megami Tensei version adds an Auto-Map, lets you do Triple Fusion in all Cathedrals of Shadows as opposed to just a few, and includes other events that generally make the game less difficult for a more comfortable experience. Shin Megami Tensei: Out of all of the stories in the main series, this one is probably my favorite as in my opinion it has the best overall handling of Alignment without portraying Law or Chaos too unfavorably compared to the other. The balancing feels like a bit of a step back from Megami Tensei II, though, and the menus can be clunky to navigate, too. (Seriously, why did they feel the need to take out -dyne Spells?) Shin Megami Tensei II: Hoo, boy. Probably my least favorite in the series, thanks to its plot being way too anti-Law/pro-Chaos and the fact that offensive magic in this game is somehow even more underpowered than in was before in Shin Megami Tensei I. Also, screw the Twelve Godly Generals. Shin Megami Tensei: if...: My favorite in terms of gameplay. Its plot is a more interesting shift towards better character writing, -dyne Spells came back and Ailment/instant kill Spells were made twice as potent to make offensive magic suck less, and there's less aggravating backtracking.