What's the best system for running a Neon Genesis Evangelion campaign? i.e. balancing huge mecha fights ans theology symbolism with high school kids growing up and subsequently breaking their minds and egos? Bonus points for allowing a GM to actively mess with the player's heads. I've tried Adeptus Evangelion but I'm not a big fan of Dark Heresy's system, so I'd like to find something a touch lighter on the rules.
Rules-light NGE, eh? I’d probably reskin Monster and Other Childish Things for that purpose. Out of the box, it’s a game about middle-schoolers withmonstrous imaginary friends that feed on relationships and are powered by psychological trauma. It doesn’t take much - just relabeling a few traits, really - for “kid with trauma-eating imaginary monster friend” to become “emotionally stunted teenager with self-loathing-fueled giant robot”, though. There’s a supplement that explicitly deals with giant monster fights, but you can probably wing it based on the core book alone if you need to.
(Someone in the notes is probably going to plug Bliss Stage, so I’m going to head that one off now: it’s not a bad game by any means, but it’s more lightly inspired by NGE than a straight adaptation; it’s not particularly well-suited to running a campaign that hews very close to the source material.)