Travel Through the Apocalypse and Become a Villain

Who said you can be proud at work if you are frustrated in love? A down-and-out young man gained the ability to travel between two timelines due to an accident. What? Do you want to exchange a nuclear rifle for a pack of braised beef noodles? No! Only half a pack can be exchanged! What? Want to exchange a set of exoskeleton mecha for a box of canned fruit? Excuse me! Two sets will do! Relying on the ability to travel back and forth, the boy built his own empire in two timelines! Fight aliens and heretics. Finally become a hero!