Easy Chess 2P

We all chess players know that there is no better option than a real physical board, but when the need for a 2 player chess challenge with a physical person strikes in and there is nothing but a mobile device in reach, this is the app you want to have.
I am just a beginner in the chess world, but something I personally hate from sharing a screen to play a two player chess game is the lack of 3D pieces. I have found 3 different approaches online for such problem: one of the players just sees the pieces upside down, the board flips each turn or the pieces are symmetrical. None of those solved my need to see my pieces normally during the other's turn. Since nowadays the mobile devices have a fair large screen, my simple solution has been to display 2 boards on the same screen, one with the pieces facing upside and the other facing downside.
Obviously I could not resist from implementing the basic intelligence we all expect from a chess app: only allow legal moves, the possibility to show aids and threats, customizable aesthetics, different game modes, detecting any game outcome (check mate, stalemate, etc), undo/redo...
There is the option to show a different level of aid for each individual player, to help beginner players like me to play against more advanced players.
It is such a pasional project that I am very open to receive suggestions.