it would be fair if you put a warning in the description of the Doom Cannon. it just said fully charged breaks tiles so i thought maybe like dyanamite so i shot it near my house so now i have a big hole, but i like that it breaks so much, just a good warning would be good.
My first experience with the Doom Cannon was a shocker. Since the quest reward gave me a bunch of grenades at the same time, I assumed those were for the Doom Cannon and it would blast grenade-sized holes in the ground. It seemed like charging it was taking way too long for what it was going to do, but it finally finished and I shot it down at the little hill right next to my house. That house ended up with a very, very deep basement.
I think the main reason I didn't expect much is that you get it so early in the game. It has a block breaking ability that's post-Moon Lord in power, but you get it right after Skeletron. That's not necessarily a bad thing, but getting it that early definitely led to lowered expectations regarding the size of its effect.