When "Charlie" awakens in the vivarium, he goes about life in general until he "catches" the water filter hose in the stream/pond. But as the scene continues, there is no way that he wouldn't notice the man-made construction of the glass enclosure or the fact that he cannot see the whole sky. Only when he roams hysterically around the vivarium does it become apparent.
Dr. Diane Brady says that it's impossible to "revivify" Charlie because when organisms freeze, it breaks the cell walls.
Plants have cell walls plus a cell membrane. Animals have only the cell membrane (though that also breaks when freezing.)
Plants have cell walls plus a cell membrane. Animals have only the cell membrane (though that also breaks when freezing.)
The fundamental premises of the film, that someone frozen thousands of years ago could survive to be brought back to life in the future, has been extensively examined by science and shown to be impossible. Even in cases of "flash freezing", where an animal was instantly frozen, ice crystal formation inside the body, and the subsequent thawing process, would completely destroy cells and make life after freezing impossible.
When Charlie is looking upwards to the helicopter, his open mouth reveals a large number of silver fillings. Such dentistry, obviously, wouldn't have been available during the stone age.
When Charlie is hanging from the helicopters runner, there is no logical reason why the helicopter is suddenly flying above the clouds. As the team member opens the door and reaches out him, presumably to pull him in, it would have been much wiser to tell the pilot to at least descend. No pilot worthy of getting a helicopter license would fly that high with a person hanging off a runner in the first place unless his motive was to kill him in an unnecessary elaborate movie-plot fashion.
When Charlie encounters the helicopter for the 2nd time, there is no shot to show "how" he got onto the Helicopters runners or how the helicopter managed to get close enough for him to leap onto it.
When Charlie awakens from his 40,000 year old slumber in his "habitat", it is a 200 foot by 200 foot concrete/glass enclosure with pumped water, fake rock formations and flora and fauna. Dialogue explains that the structure was already in place, for studying bears. But no remote outpost like that is ever constructed out of poured concrete, huge steel girders and glass sun roof. They are always preconstructed sections that connect together.