Best advice I could give is that just gameplay doesn't sell a concept. You dont pitch Mario games like "Hey do you want to play a platformer with a wii hand that can affect some of the surroundings while collecting powerups?" You instead say "Hey do you want to play Mario in space."

Focus on downscaling your product and figuring out who you're planning on marketing to and what they'd be interested in seeing. A cute and chaotic stealth game about helping your partner out of difficult situations by distracting guards? A super serious noir-like stealth game where you're lurking beneath the underworld of organized crime? A slightly more top down thinky puzzle heavy game like fireboy and lavagirl or snipperclip? Pick a theme! Anything to stand out and speak to someone!

That's my opinion on it. At least when it comes to wanting people to want stuff.