There Is a Crossing Door in My House

An ordinary young man who failed to start a business unexpectedly discovered a time-travel door in his bedroom, and his ordinary life started sailing! Trading strange goods from other worlds and earning countless gold and silver! Anyone who has learned otherworldly combat skills and magic can defeat him! High-tech and advanced weapons in the technological plane are at your fingertips! Reclaim the wilderness and station troops on the wild planet to establish a lasting hegemony! Let's watch the protagonist become bigger and stronger step by step, becoming invincible in the world!