well for starters one is a side scroller, terraria has way more bosses and items and stuff, it also has city builder elements because you can build houses and people will move into them, and you can buy stuff from them. there is not "one boss" there's hundreds. dont go saying stuff like that, i can tell you have never even played it. it is more of an RPG than a minecraft-type game. theres a lot more stuff to do, you can fight goblin armies to defend some dudes crystal, theres more of a story, you have to fight cthulu to kill the moon lord, then stop the corruption/crimson and save terraria. oh did i mention crimson and corruption? stuff that spreads across the world making tough monsters spawn in it. it can be put back to normal by throwing purification potions on it that you can buy from a druid.
in conclusion it is not copy/knockoff in any way, 505 didnt even know minecraft existed when they made it, it is completly different, you have never played it, you are a child, you need to get off the internet because its not a safe place for kids.