This game is not modifiable. Wild City is an online multiplayer (MMORPG strategy) crime mafia game. This means that it has an online server which cannot be used to obtain items,perks,etc. Everything is stored on their online server.
try decompiling the signed libraries. usually held in /data/data/(vendor name)/lib they are .so and when you decompile them its in ASM so either be really good with ASM or hope they didnt use a good C compiler and it left some of the variables and calls.