Darn...(Good night)

I know the feeling of getting caught up in playing a game. I play Cradle of Empires on my tablet and sometimes I can't stop playing until I've beaten a level or competed the daily quest in order to go some way to reviving the lotus! I haven't opened the cave yet and I'm really desperate to do it but you need to get certain objects and you get them by playing games but only if those specific objects are highlighted at the start of each game if they are available to be collected. The ones I need haven't come up yet and I'm getting impatient. I'm thinking you might have to reach a certain overall level before they appear ready to be collected.