Simple, system-neutral mecha combat rules

I cooked these up to prepare for a game. See what Veeky Forums thinks.

Basically, you roll up the mechas as if they were human characters. (Other races are supported, but this post will use exclusively "human" lest things get too complicated.) Physical stats, maybe perception, but not mental stuff.
How's their equipment? Just take regular human gear and scale it up. A light laser rifle becomes a heavy mecha-buster, for instance. A longsword is a building-cutter. A plate mail turns to double-layer adamantine shell. And so forth. You can come up with better names than I just did.
Then put a fully statted human inside. Replace his physical stats and equipment with those of the mecha's. Make him fight another mecha with another human pilot in it.
You're basically done. Go nuts.

Human versus mecha?
Don't even bother making rolls: the mecha wins any physical contest, including combat, usually instantly. It might take a little longer if there's a whole lot of humans, but not by that much. Its pilot can then decide what to do with the loser or losers, and how the victory is concluded.
Most agility rolls, however, such as difficult terrain, will go to human. Again, no rolls needed.
Mental and social rolls are made as normal.
With above limitations in mind, the human can come up with some bullshit scheme to allow him to get up there and capture the mecha for himself. Up to GM what works and what won't: if he thinks it's too bullshit, don't complain. If it involves physical non-agility contests, it's probably going to fail. It'll probably involve some human-on-human fight at the end anyway.

Optional rule: Even bigger mecha, size categories.
If you encounter a mecha that is as much bigger as normal mecha as those normal mecha would be bigger than humans, then it's a size 2 mecha: they're created as normally, including scaling up the equipment to another level, and any normal (size 1) mecha counts as human when fighting against it. No human can even try to capture it anymore, but a size 1 mecha can give it a shot.
Even bigger (size 3+) mechas are also possible. Just keep scaling everything. You'll always need a mecha precisely one size smaller to make an attempt at capturing it.

How do you think it'd work out?

Made a bit of a challenge for myself when I put a mech in DnD. LOOOONG running campaign, and the player was very interested in Dwarven Fighting machines (i.e., mechs).

Trying to find balanced rules by using Apparatus of Kwalish as a base, and more HP.
This Thread may help though.

Woah, hold the fuck up.

My guy beat up a giant a few sessions back, and now you tell me that he'd just instantly lose against a mech of about the same size? Like, the fuck's up with that?

A good question.

Mecha, you see user, is not just about your size and strength. It's about your heroic spirit and indomitable will - something that only piloting a giant robot can truly realize. A giant without this advantage is just a big human - your fighter inside a mecha the size of said giant could beat them without much trouble.

Stick that giant to a size 2 mecha, however, and watch the tables turn.

Okay but then how come a size one mecha can't try fight a size 2 mecha?

>Don't even bother making rolls
So portable anti-armor weapons don't exist? You can't ambush armored foes and destroy or at least cripple them? Shitty system.

>Don't even bother making rolls: the mecha wins any physical contest, including combat, usually instantly. It might take a little longer if there's a whole lot of humans, but not by that much. Its pilot can then decide what to do with the loser or losers, and how the victory is concluded.

>tfw spacerfags think they're immune to a Carlos 84mm through the rear armour.

>portable anti-armor weapons
Count as +1 size for damaging things. If you lose initiative or the mecha otherwise gets to try and hit you, you're still toast.

There isn't a lot here. All you did is make a megadamage system based on hugeness, so okay? Big thing kills small thing unless small thing can hide/cover, now what? What's that add to your game? How often is it going to come up? What is the rest of the game like?