These are one of the concept design I did for "Coin Master", a successful mobile game belongs to Moonactive. Every world building leans on a theme, which in this case here it's "Vasco De Gama". Vasco was a Portuguese explorer and the first European to reach India by sea.
This square images above is planned ahead to fit all the mobile versions. The game is concentrating in the 5 figures/items in the middle and the player should aim for upgrading them into their more developed version. Here are a few examples for the characters' levels and their destroyed ones in parallel.
Every world has a slot machine and a sticker. The slot machine is adjusted to fit its theme.