Ancient Dragon is super lame as a boss in tactics and overall design. Just a big clunky idiot with a insta-kill fire attack. He was SUPER easy back when the Gower's Ring was still useful, which is now deemed Gomer's Ring (pointless).
All you gotta do is either A) attack his feet and follow the tail whenever he's in the air, or B) stand between his two back legs with the camera facing his head and swing away at his feet until he does the stomp then go to the other foot, rinse and repeat, reason to keep the camera adjusted toward his head is he'll often do a under his body fire breath so you'll need to see it coming and just move to the left or right of whatever leg. Then continue. Beat him at Bonfire Intensity +10 using a +10 Heide Knight Sword, full hollow/half health (Red Tearstone always on just in case). Either tactic he's weak to lightning and Dark buffs/infusions.
Really sad to see From go from the amazing Kalameet boss to these lame as hell Dragon's in #2. Not even any incentive to get more creative and add extra challenge with a tail cut weapon or "beat this way = item". Just, sad. I loved the Kalameet fight, and hoped to see more of that awesome design done in different ways, but nope.
Edit: And a few other retarded annoyances this games has. I'm sure we're all aware of the utterly broken mechanics in many ways and I've already been over this ground so I'm not going to just add to that fray. But here's some things that were obvious things to do, small things that were just neglected for the sake of it.
-Being able to despawn all enemies into extinction, whoever thought that was a good idea was obviously the same guy who thought giving the boss intro's that bloody stupid pulse was a "good idea". They tried to make a excuse for this with Bonfire Ascetics, but that's a super weak excuse, why not just have the Ascetics function like "Soul Tendency" from Demon's so rather than respawning the enemies, you just make them harder, open up more Tendency events, and get far higher loot drops. SM obviously BADDD idea, P2P SL-matchmaking was way better in Dark1, that whole stat should have just been the Item Discovery stat, but now we don't even get that visibility... Just a hope and prayer that gear and Luck coins will pull through...eventually. Stupid, RNG should be replaced by increased drop rates for skillful play, NOT randomization. That's always been a gripe for me with the whole series and why I never got Plat in Demon's. And don't let it carry over to NG+ so you can up the challenge even further this way.
-Repairing and Upgrading weapons/armor. Easy fix here, just make the player use the Blacksmith's until they obtain their hammers, then at any Bonfire you can repair broken shit or upgrade anything you want, aside from Infusions. This was such a simple reward that it baffles me they thought it was a good idea to make the player go out of their way ALL THE TIME to repair/upgrade. Same for leveling, you should have had the choice of some kind to be able to level up at any Bonfire from the start, maybe by killing the Maiden and getting a item, but they had the shoehorn her into the plot so that wasn't doable, but since she's in fact a illusion anyway, it still makes sense to allow players to kill her at the start in Majula and lvl from any Bonfire, could have done some good for alt story stuff too, but too much to ask I guess, or too creative?
-Promo items - W T F! Seriously, WTF. Why can From not do a simple rename for these weapons? Or god forbid maybe a slight move set and/or stat effect and scaling changes? Moonlight Longsword coulda' been awesome, got tons of ideas in my head, does From...no. Just a Blue/Green Longsword. Yeah, just lazy PR development and a lack of real investment into the creativity of any of it.
-Lack of variety in the "weapon type" move sets overall had me really disappointed. Especially when they totally retconed and nerfed the almighty Reinforced Club with zero Bleed effect! WTF! Same for the Great Scythe...no Bleed Effect, are you kidding me? Mace move set same as Morning Star same as Club same as Reinforced Club (what happened to the awesome Club/Reinforced Club/Giant Blacksmith R2's) and so on, Spears, Halberds, Greatswords, Straight swords, list goes on with very few exceptions. Possibly the worst offender is the terrible step back the Zweihander got in it's R2...geez! Not to mention the overall total order of magnitude step back in all types of character animations and weapon animations. It's really just a shame to see the lack of real work put into it. Stone Soldiers are a good example in how they sort of swing their spears around attacking, yet the player just gets the exact same move set of most other spears... Just, amazing to see that. Probably the best weapon and move set added was the Bone Fist imo, Santier's Spear and maybe Twinblades. But overall, it just sucks.
Anyway, enough of me abusing DkS2.