I'm glad I could help you,But I only know some basic skillsJust like with modding the resources.arsc (There are some software texts exist in such places, so I can Translate into Chinese),Or modify some images(Most of them are game sprite, such as this one) within the software or replace rom in some bundled game emulators(like myboy emulator.In China, someone used this emulator to create an fake Android version of Sonic Advance.)
I have been modifying this version since a few years ago(Most of them involve modifying textures and replacing music),But at that time, we used a cracked version. Like the normal version,the first thing to do is clear the first level of the TimeAttack mode before playing all content.Then close the pop-up window(Originally, this pop-up window was used for paying to unlock the game),I don't know which version you archived and which version are you using?