I think I could've beaten stage 12 if I hadn't spent 16 on pointless relic bags just before this round. There's definitely room to optimize, but I think some version of this setup is the best that you can do.
Maybe it is, if do you keep the game combination base and no use duplicated relics. But there is a lot of better plays with both of this features. Anyway, the green house is better than the red car.
