While a ship, the Lexx was primarily designed as a weapon that could destroy planets, so I'll go for The Lexx.

Only if you can't consistently, precisely, and accurately target a human brainstem.

Gonna have to go with something like a lasgun from 40k. Given the restrictions of no vehicles or weapons platforms and nothing magical.

The lasgun is a mass produced rifle which hits something like a modern day 50cal and has basically infinite ammo by being able to recharge the battery packs from literally any available source including sunlight and chucking them in a fire.

Think of the tech advances we could get from that. The battery alone would change how tech functions. Given how ass backwards the imperium is about tech there's also a decent chance we could work out how to reproduce it pretty quickly too.

Other good options are fallout laser or plasma guns for similar reasons. I'm trying to remember if those guns take fusion cores because we've been working on that for a very long time.

Halo 2 energy sword

I'd like a Death Star, you can certainly trust me with a Death Star.

Why pick something that can be destroyed by a single transphasic torpedo?

Wish I Had a Portal Gun

John Creighton's blaster pistol from Farscape.

I may be misremembering it but, I think you are forgetting the most limiting part of the portal gun:

Phasers on stun!

Scale is important. Yes, the moon is round, but local flatness could be within the tool's tolerance. Even a surface plate (used by machinists a reference for flatness) has local peaks and valleys if you zoom in on the surface.

Not even sci fi - I always wished that when I had each baby I was issued 5 tranquilizer darts. Not more than 5. With each, there were about 5 times I wished I could just blow a dart at them and have them immediately asleep.

Sci fi I just want a de-escalation gun.

It was a rotating barrel railgun, right? Water cooled?

The ZF-1.

it’s light. Handle’s adjustable for easy carrying, good for righties and lefties. Breaks down into four parts, undetectable by x-ray, ideal for quick, discreet interventions. A word on firepower. Titanium recharger, three thousand round clip with bursts of three to three hundred, and with the Replay button, another Zorg invention, it’s even easier.

was there anything special about it? I mean its something he picked up right because he was from earth.

thats only like a few seconds!

One that immediately eliminates all billionaires and blocks their existence forever.

The Farsight XR-20 from Perfect Dark that can see and shoot through walls.

For no particular reason.

If you get a portal gun, you get the gravity gun included

Yeah, I'd shoot two portals in a vertical line

Undo my belt, lean in and

Change pants without having to look down

Also I’d suck my own diiiiiiiiiiiiiiiiiiiiick

Yes. It could technically be a weapon if you placed a portal up high, and another on the ground under someone.

Sonic Screwdriver is pretty much a magic wand with lights, so I choose that.

*Okay, you know what? I'm gonna pretend you didn't say that, because that is quite possibly the stupidest thing I've ever heard you say.

Pick up a car and release. Much death.

Not really. You need to press a nail gun against something to fire a nail.

Is the idea that it takes the easiest method to kill something?

I think they chose it mostly because it ejects casings upwards, which gave them more freedom for placing the actors closer.

Well regrettably my wife didn't really get the hang of portal and we're the only two who live here. Maybe when I have a friend over. I'm kind of old and the only friend I have that really plays games lives in the UK. We pay together online. If you're interested we've played:

Borderlands
Borderlands 2
Borderlands 3
Tiny Tina's Wonderland
Borderlands the pre-sequel
Grim Dawn
Aliens elite team
Warhammer 40000 space Marines?

And we're currently playing Aliens Elite Team 2.

I may have forgotten some.

The best way to use the Portal Device in Hedgewars (especially if you can shoot one end above water), given it doesn't end your turn.

Plus a tempting red button

Phys gun from Gmod

If we really want to get into the specifics technically everything is moving. Could maybe that as long as the object is stationary relative to nearby large mass but then that would start to strain the moon shot since that is a separate large moving mass being linked to another moving mass

I think with drugs or high blood sugar you could lie to it

Its gravity gun lol

Be your own reach around

It's actually a Zero-point Energy Field Manipulator, but yeah, someone else used "Grabbity gun" and I loved it. Great homophone and entirely in line with Valve humor.

But I do believe it canonically is called Gravity gun.

Wasn't that The Diamond Age?

Edit: Nope, I just can't remember for shit anymore.

You have not read the book, have you?

Maybe closer to OPs restrictions.. Cyclone Body armour!

A Gun That Can Kill The Past

Have loved the Marauder since MW on my Tandy. Dual ppcs and a long range autocannon? evaporate some jenners and locusts before they can even react to your presence

Uhm, okay?

E: took me a while for the reference 🫠

It does!

and tele-fragging: stepping into the same space as your target, theoretically exploding them

lol someone can finally play go fuck yourself

They're scientific instruments, not water pistols!

"Water cooled" in that they submerged the nuclear heat-sink array in the ocean to keep it from destroying their boat.

I don't think this one would work, since they don't occupy any space in the flat plane the portals appear on. You're just making doors.