There are some great action sequences that pay homage to the previous films and other sci-fi classics like Aliens and The Matrix
I spotted the following "homages" (more like complete ripoffs, if you ask me-and since no one did, I'm just saying):
Overall look of the scenery- Saving Private Ryan
Chase scene in diesel engine with cow-catcher welded on the front (even had the windshield getting shot out)- Road Warrior
Conflict between main character and "headquarters", river terminators, Marcus' scene @ SkyNet- the Matrix movies
Marcus escaping from the resistance- the great escape (he even crashed the motorcycle the exact same way as Steve McQeen)
Marcus' visit to Skynet- an amalgamation of I, Robot, AI, and The Matrix.
The big terminators- they didn't just look like transformers, they were transformers
Transformers, er Terminators picking up humans and dropping them in baskets they were carrying- War of the Worlds
Fleeing characters bringing the bad guys down on an enclave of refugees- 28 weeks later
Terminators using facial recognition software to track fugitives- Minority Report.
Opening up cells in SKYNET to reveal big, bad, monster- Resident Evil
They even ripped off other terminator movies! The scene where connor is fighting the T-600 in a factory?
These are just the ones I could think of sitting here. I was waiting for Reese to whip out a lightsaber and and tell John Connor "I am your father", to which Marcus would have replied- live long and prosper.
Also- how could John Connor destroy a terminator by shooting it? Why would terminators capture people instead of just killing them? How could they knock Marcus unconscious? How did Marcus float in the water? Don't they have someone who asks these questions?
Do ye not therefore err, because ye know not the scriptures, neither the power of God? (Jesus)