Could you have a silver metal and a brown metal then with some color accents? I'm just looking for a little more variety there, since you guys seem to roll out ship skins pretty fast. How about including the Sao Paulo city as the main Zombie course but being able to unlock the rest anyway, just to have more tracks to run on. I do like the buddy idea, although I'm going to personally call him the Mysterious Stranger simply because I play too much Fallout If you would do that, then I think the best thing to do would be to have the Zombies continue to spawn in group each sector, until they reach the limit of that wave, and then, once they're all killed, you have a free lap to meet up with the Mysterious Stranger, and then you could do a leech beam like effect when he transfers energy to you. I think it would be cool to have a Boss Wave every handful of waves, and have your buddy join in for that wave. Now I would suggest that the boss be coated in an all out badass red skin, that would be cool