NO; World is not an illusion but real. All our deeds, good and bad will be counted and will be judged accordingly on the day of judgement. We all have feelings and emotions and that is real and not an illusion. In Quran, word delusion is used for the world as follows: Every soul will taste death, and you will only be given your [full] compensation on the Day of Resurrection. So he who is drawn away from the Fire and admitted to Paradise has attained [his desire]. And what is the life of this world except the enjoyment of delusion. (Quran, Āl`Imrān 3:185) Know that the life of this world is but amusement and diversion and adornment and boasting to one another and competition in increase of wealth and children – like the example of a rain whose [resulting] plant growth pleases the tillers; then it dries and you see it turned yellow; then it becomes [scattered] debris. And in the Hereafter is severe punishment and forgiveness from Allah and approval. And what is the worldly life except the enjoyment of delusion. (Quran, Al-Ĥadīd 57:20)