The idea isn’t original, but its alright if you want to try it. If you want to make this concept feel more appealing, you could add more unique features that make the game feel very interesting. Maybe some special maps where the player has to kill the giant while avoiding instant kill floors? Killing the giant with a vehicle(that fits the map). Or even giants being able to throw certain objects at the survivors, like a table.
Speaking of maps, they should also feel special. I’ll give you an idea, how about a map about a child’s bedroom? Survivors get spawned in a toy box(with a way out of course), and the giant gets to throw other toys at the players, like a lego brick for example.