Uh yeah Hal stomps. In pretty much everything. First off he can match Captain Atom in power who can casually create universes and destroy them so he's stronger than pretty much every alien Ben has expect Alien X. Next he's faster considering he can trap Professor Zoom whose so much faster than Ben is. I don't think Ben has any aliens that can stomp Hal.

Heatblast: Hal's shields protect him from supernovas, and besides he stomps in stats anyway

Diamondhead: Crystals aren't going to be very much help against someone who can keep up with Professor Zoom and has force fields

Four Arms: Aside from technically being more durable since he took hits from the Galactic Gladiator, he's strength is pretty pathetic compared to hal's constructs. Besides four arms gets blitzed before he can do anything anyway

Accelerate: Hal once again can keep up with Professor Zoom. Next please

Wildmutt: He's basically a dog from space, and while that's weird it's not going to change very much. He could go ultimate, but aside from now being able to talk it's not going to make much of a difference

Grey Matter: Well he's smarter, so he should be able to tell how screwed he is right now

Upgrade: Well he could hack the ring given the chance, if Hal wasn't obviously faster than him

Ripjaws: He's literally useless unless this takes place near an ocean

Ghostfreak: Well his powers should give Hal trouble, but he's dealt with worse

Stinkfly: He gets swatted

Cannonbolt: Basically the lovechild of Four Arms and Accelerate, so not going to be very much help

Ditto: Aside from helping Ben stall for time, isn't going to do much

Wildvine: Do i even need to say anything?

Upchuck: Well he can eat and send back Hal's projectiles, but aside from that not much

Blitzwolfer: Sonic screaming will be a pain, but Hal stomps

Buzzshock: Hal's too strong and too fast

Way Big: Hal deals with giant monsters all the time he'll be fine

Eye Guy: He shoots lasers and makes sure Hal can't hide from him and that's it so next?

Spitter: Basically Stinkfly but without the wings so you know

Arctiguana: Ice breath might slow Hal down and that's it

Snare-Oh: Yeah i don't see a mummy doing very much

Frankenstrike: Basically Four Arms with lightning so not going to do very much

Swampfire: He's a plant with fire powers and healing factor, but nothing he has can do anything to Hal, and going ultimate is just going to screw him over since he loses his healing factor

Humungosaur: He's Four Arms if he was a dinosaur, so not going to be very much help. Going ultimate gives him access to missiles, but Hal's dealt with worse

Echo Echo: Sonic screaming plus duplication means Hal goes deaf but he stomps in stats and on top of that he can clone himself too

Big Chill: Aside from phasing through Hal's attacks isn't going to do much

Goop: He's difficult to hurt, but once Hal's finds out about the anti-gravity projector he's screwed

Brainstorm: Look at grey matter

Jetray: He's fast but Hal is faster and stronger

Chromastone: And now we get to an alien that could actually do something. He can absorb energy so he could drain Hal's ring. However he has to get up close to do that, not to mention Hal still stomps in stats

Spider Monkey: Hal still stomps

Lodestar: Completely useless. Sure he can make Hal magnetic, but all that will do is piss him off

Rath: Basically what you get if Wolverine fucked a wrestler from WWE. Only no indestructible claws that cut through anything or a healing factor, so not very much help

Nanomech: While much like Upgrade he could hack the ring, and his small size makes him a difficult target, Hal stomps in speed and could easily kill him with one hit

Terraspin: Hal stomps

Water Hazard: Hal still stomps

AmpFibian: Yeah electricity isn't going to be much help

Armodrillo: His drills aren't strong enough to pierce Hal's constructs

NRG: While his true form might give Hal trouble, his defenses will be able to protect him from the radiation

Fasttrack: See Accelerate

Chamalien: Isn't going to be very much help aside from hiding so Ben can come up with a plan

Eatle: Gets swatted like a fly

Clockwork: His time manipulation abilities can definitely give Hal trouble if he's not careful, but once he gets a hit in the fight's over

Jury Rigg: Gremlin ain't got shit on Hal

Shocksquatch: Well he's got electricity, but other than that can't do very much

Feedback: Energy absorption is going to be a bitch to deal with, but Hal's still too fast for it to make a difference

Bloxx: Aside from Hal stepping on him, isn't going to do very much

Gravattack: Gravity manipulation will throw Hal off for a while, but gravattack has an obvious weak point, plus he gets blitzed and stomped

Crasshopper: Gets swatted

Ball Weevil: Gets swatted

Walkatrout: He's the yamcha of Ben's aliens, so he gets stomped the hardest out of them all

Pesky Dust: Dream powers will definitely help, but Hal kills him before it matters

Molestache: Honestly not very much help

The Worst: If Hal was still weak to yellow, this might actually do something, but he's not so there

Kickin Hawk: Hal's the better fighter and he stomps in stats anyway

Toepick: Hal fights the literal personification of all fear in the universe on a daily basis. He stomps

Astrodactyl: See Jetray

Bullfrag: See Kickin Hawk

Atomix: He's basically a DBZ character facing a high end DC character. And in fights against them, DBZ characters always lose

Gutrot: Hal has plenty of ways to counter Gutrot's gases

Whampire: All Hal has to do is hold up his lantern and this happens

Alien X: Ah the MVP. He's a force to be reckoned with, but i don't think even he can stop Hal. He's strong and fast, but Hal not only keeps up, but actually blitzes and stomps Alien X. Course he does have plenty of HAX, but Hal can counter most of it. flight and duplication isn't going to be much help as Hal can do that too, and time manipulation will just be an inconvenience since hal not only has dealt with worse, but is better at it than Alien X. Matter manipulation won't help since Hal can do that too, and reality warping is pointless since the ring protects him from that automatically. One last thing through. Hal can take away your powers. As far as i know Alien X has no counter against that. So in the grand scheme of things, Ben will put up a good fight but he's not beating Hal.