I can definitely vouch for DH's Smashes being sneaky, since charging them boosts their range (most noticably his FSmash, which in terms of sheer KO power, is definitely his strongest one, but it's also his slowest one), and in the case of his F & D Smashes, they lower his profile as well, protecting him from certain punishes (Falcon's run-up grabs, for one, and possibly the tip of Ryu's FSmash, but I've not personally tested that yet). His run-up USmash is definitely legit, since it's 7 frames, but he'll have to wait a while before it'll actually KO you (130+%??).
As for traversing DH's arsenal, we do have:
- FADCs to handle Gunmen's shots and even Clays, but only if they're not shot-up. More likely, they'll be shot-up at seemingly the instant they're thrown out, and if/when that happens, try to FADC forward ASAP, otherwise the shots will catch you (and if DH's nearby, he can follow it up for a bigger punish). FADC-ing through default Cans is NOT recommended, since it's a multi-hit move that will cleanly beat your FA.
- Tatsu can beat Clays, but again, only if they're not shot-up. It'll also OHKO Gunmen (and hit DH if you catch him setting them up) and kick Cans if they're in the air. You'll sail over grounded Cans from a distance, but those can be B-pressed if you're directly over the Can to challenge your Tatsu.
- SRK-motioned DP will let you bypass everything, due to its invincibility, but its horizontal range is severely lacking. If a DH tries to approach you (from the air, even) with any of his arsenal out there with the intent to cover him, this COULD be a decent option.
- Hadoukens, even its weakest B button version, will OHKO Gunmen, clash with Clays, and push back Cans, but only if they're in the air.
- Red Hadoukens will let you pierce & KO Gunmen, and even hit DH if he just set one up. It'll also pierce Cans, possibly allowing you to hit DH as well if he's close by. Sadly for us, even Reds will clash with Clays.
- All Hadoukens, even the Reds, will sail right over any Cans lying on the ground if you chuck them from farther than point blank range.
We also have our traditional universal options (Parry-- er, powershields, (spot)dodging, jumping, rolling, etc.) on top of all this. It's pretty cool & fitting that an infamous Fireball+Uppercut trapper from Super Turbo and a pseudo-camper in SF4 would have ways to get in on camps as fortified as DH's (who would be most like... Remy from 3S if there were no Parries?? Area from the EX series?? Yatterman-2 from TVC?? A handful of characters with strong post-hard-knockdown okizeme like Frederica Bernkastel from Ougon Musou Kyoku Cross (the Umineko no Naku Koro ni 2D fighter), Komachi & Alice from Scarlet Weather Rhapsody (Touhou 10.5), and Kohaku/Hisui from Melty Blood???).
I play an aggressive rushdown DH, so I likely do half of Ryu's work in approaching me for him, much like how upclose rushdown characters like Yun & Cammy do half of Zangief's work in approaching them for him (which does partially explain why SF4!Yun struggles with Zangief, since he doesn't have parries to disrespect his moves with like what he could do to Hugo & Alex in 2I/3S...). However, DH does outrange some of our melee moves, like his FAir & UAir & FTilt. Some of his attacks are also pretty fast as well, like his 4 frame jab, his 6 frame DTilt & NAir, and his 7 frame FAir & BAir. Upclose is where FAs become more useful, since the only multi-hit moves he has upclose are his jab strings, UAir, DAir, Clays (if shot-up), Up 2, default Cans, and his Smashes. The amount of combo damage we can do to him generally exceeds what he can do to us, unless he can get Clay (shot-up) --> (tippered) FAir x? --> (Closeup sweetspot) NAir juggles going.
If DH gets to put on Customs, expect 3121 or 3122.
Zigzag Can is his anti-air that, if mashed & positioned well, can rack up 20+% in 1 go.
Duck Jump Snag is practically our DP, minus the invincibility. He loses recovery distance if he runs this, so he'll want to be at a walled Omega stage (his best stage, btw) to be able to wall-jump his way back to the stage. This will also challenge our upclose aerial edgeguards, and its multi-hits will body FAs.
Quick Draw Aces will basically be a faster Clay in terms of distant poking. So long as you don't KO these Gunmen, he'll be able to play footsies as well as you can. Since you have more anti-Gunmen abilities than some other characters, DHes may pick this to have a usable Gunmen whose shots will likely come out before getting KO'd.
Stages: Expect walled Omega stages if possible, since traversing his arsenal becomes more difficult without platforms. Try banning them ASAP, since DH can wall-jump off of them to boost his recovery (especially if he's running Up 2) and you can't (he never really could in any part of his series, could he?
). Smashville's single platform CAN make the difference in getting in on him, but its similarity to FD is troublesome. T&C is less similar to FD (until the transitions, that is), and its lower ceiling can help us KO him sooner.
As for stages to try to take him to, Castle Siege, Duck Hunt, Delfino, and Halberd would be good ideas, since the 1st 2 ruin the dog's projectiles (CS's 1st transformation, at least), and the latter 2 boosts our good KO power further. Lylat Cruise, Miiverse, and Dream Land 64 would be decent ideas at least, due to how closeby the platforms are.
's Neutral Air is slow, Forward Air is slow, Down Tilt is probably 
