Alien - Somewhere around the 1-2 ton range. Their strength is never truly shown, but they can hurl their bodies over 20 feet, they can rip open gigantic steel objects, etc. They are viscious strong.
Predator - Somewhere around the 1 ton range.
Robocop - Probably 600-800 lb range, his body is strong, but the way he's built prevents full range of motions which can help a lot in lifting and generating force.
Terminator - Probably around 1 ton
T-1000 - Around 1 ton
Terminatrix/ TX - Probably around 1-2 tons.
Jason Voorhees - Most likely around 600-800 lbs
Uber-Jason - Most likely around 1 ton
Freddy Krueger - Very little. He usually distorts reality
Michael Myers - Same as jason
Goro (Mortal Kombat) - Probably around 2 tons
Zangief (Street Fighter II) - Around 800 - 1400 lbs
Mr. Incredible - The guy from the Incredibles movie? Never saw it.
Aliens aren't that strong. Their agility, claws, spiked tail, acidic blood and stuff are their power. They are weak otherwise. They tear things apart because they have the tools to do it, not because they are strong. Hicks managed to overpower one, and Ripley in that clunky machine thing overpowerred the almighty Queen.
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Hicks didn't overpower one. What the hell are you smoking? A full trained marine, braced against a wall, using his leg barely held an alien that was trying to slide into the room, and wouldn't have held it much longer if he didn't shoot it.
That clunky machine was a machine used to move boxes around. They are used to load things, they are more powerful than forklifts. That thing could lift 2-3 tons easily.
Aliens, especially in the comics and books, show they are much stronger than in the movies.