My son is playing the game and he is confused that after GAME OVER he has to start playing again. NEW RUN ? I don't know anything about the game but I assume it is ROGUE style, so there is no SAVE and CONTINUE and gradual conquering of levels, game maps like in PvZ ?
This game has no end. A Game Over does not mean that you have lost, it is just a marker of how far you have gone, as this game does not have levels. It is endless. It progressively gets harder the further you go and eventually, you will lose no matter what. The aim of this game is not to 'beat' levels but it is to see how far you can go. Losing does not mean you have to restart from the beginning, this game has challenges you can complete to earn things to help you in later runs of a game, hence the rouge-like aspect of this game. So while it is not like PvZ where you gradually conquer levels and eventually beat the game, you do gradually unlock things untill you have unlocked everything and gone far enough into a run to feel that the game has been beaten.