If you’re looking at two-player games, definitely check out Tim Koppang’s Mars Colony and 39 Dark. I can’t vouch for them directly, but I’ve played his Hero’s Banner a few times and it’s wonderful.

Ref: http://www.tckroleplaying.com

Re: Cortex Plus, I’ve had loads of fun with Marvel. I’ve played a little Leverage and Firefly and enjoyed them a lot, but Marvel has the Doom Pool, which is the coolest GM tech ever.

Re: OSR, my once-fervent interest in it has cooled a lot recently. I now care less about the OSR as a whole and more about specific games and creators: Tékumel, Kevin Crawford, etc.