I can say the same for any battle in CoC then. Any hard fight in CoC can be put down to one of the thing you said. The only reason the sandtrap is a threat is because the desert is its home turf. Mountain goblin is hard because she is something like 100 years old and a very adapt mage. The Minotaur is only threatening cause it is biologically stronger and larger than you. The Harpy Queen is home turf and a much better spell caster than you.I'm calling game mechanics on the myr rifle. Also the people you listed as actual threats are people using equal or better tech to yours, are older/more experienced than you, are simply biologically superior to your ass, and/or are on their home turf.
You see where this is going even then it doesn't change the fact that in the second area you get access to The Lake allows you to find the the strongest standalone weapon in the game. Also their is a random traveler that sells potions that magically make you smarter or another that makes you both stronger and more durable. To my knowledge the only truly hard fight is against the corrupted goddess tree which you have to go out of your way to fight.