Need games with GIANT ROBOTS

Type in "mech" in the steam searchbar. Many will pop up.

all steam games tagged as "mecha":
store.steampowered.com/tag/en/Mechs/

is Armored Core on PC?

Gun Metal is old, but it's on Steam and it was alright.

Shogo: Mobile Armor Division

A Gurren Lagann game on Steam would be so OP.

EDIT: Astebreed looks cool, if you like Shmups games.

I used to play Hawken before it was launch on Steam and was prety fun, some game modes like Siege are really fun, also the microtransactions were only for cosmetics, the most of the add ons and mechas can be unlock by playing.

Slave Zero.

i highly recommend gundam extreme versus (PS3), armored core (PS2/PS3/xbox360), mech platoon (GBA),SD g generation gundam (PSP/PS2/ WII) and zone of enders (PS2/PS3)

Zone of the Enders for PS2/PS3 is an awesome gundam-like game

MvM in TF2? :<

Lost Planet 3!!! EDIT: Or any Lost planet for that matter...

Gigantic Army....sort of.

Binary Domain

-Project Nimbus

-SHOGO

-Gun Metal

-Supreme Commander

-Sunrider

-Every Strike Suit

-Hawken

-Airmech

-Anomaly 2

-Front Mission Evolved

-Ether Vapor

-Astebreed

-Metal Gear Rising

-Mechwarrior

-Blacklight Retribution

-Natural Selection 2

-Lost Planet

Mech Warrior Online.

Strike Suit Zero
F.E.A.R 1 or 2 (can't remember, but there's a part where you control a mech.)
Red Faction Guerrilla (destructive mechs!)
Titanfall (Didn't play, but I know it has mechs...)

Transformers: War for Cybertron

Transformers: Fall of Cybertron

And don't even bother with Rise of the Dark Spark

Gunhound Ex is a mech game ,and it's cheap during the sale.

Astebreed
Gigantic Army
Gunhoud EX
Dark Horizons: Mechanized Corps seems a good bet if you're willing to try early access games.

Metal Gear Rising and/or Binary Domain maybe, if you want to fight giant robots without controlling one yourself.

Drunken Robot Pornography ?

TF2 has big robots for you to kill.

R.A.D and Ring of Red for the ps2.