Ouch !
1st wins as UV, conqueror, and first mortuary cleared (without using the nuclear BFG !?! ). Very impressive !
Call it experience if you prefer, but I confirm your run is a nice demonstration of skill.
Not all the builds play similarly, you have at least... well, 2 different builds ! (ranged and melee), and 2 diffrent difficulties (UV and N!. Respawning monsters change a lot of things)
Then, the challenges, of course, but if you're good enough to play damageless, you can own most of them (and since playing damegeless IS possible... :/). In other words, only a few are interesting.
For me, AoRA is. AoMs or AoP can be interesting once, just to check how the game plays without heal or powerups, but I don't like this kind of challenges, which basically just mean "don't get hit", while it's already what all the gameplay is about.
AoLt/AoMr/AoPc/AoOc can be fun to try, even if they are quite easy too.
I agree that the game is way too repetitive. Once you understood how cornershooting works, you don't want to play a difficulty lower than UV, except maybe for challenges, and once you stop getting hit, this doesn't change much anyway...
I was hurt once in the entire ordeal, but that was from accidentally stepping in lava. Someone ought to nerf that really.
* Evilpotatoe is sure someone would be glad to @Tormuse
Do you still play on lower difficulties, except for 2devish challenges like your full pacifist ? My last HNTR game was an AoHu (a survivalist tank xD, since all my Cateye died one-shot to boredom), and my last HMP game was for a strongman badge. The current cornershooting just makes the game too easy on lesser difficulties...