I have at long last finished playing through the excellent horror series Penumbra by Frictional Games (2007), a smallish indie game studio based out of Helsingborg, on the southern tip of Sweden, just across the channel from Denmark.
They note in the credits that the Penumbra games use an open source C++ physics library called Newton Game Dynamics. The wiki page for NGD says it is also used on Frictional’s forthcoming Game SOMA.
One if the things that I think is done pretty well in the Penumbra games is the free form interaction with the environment. It’s is kind of similar to Bethesda’s Elder Scrolls games, but I think they do some unique things with container and door manipulation, even if it is a bit tedious at times.
It’s worth noting that Frictional has stuck with the NGD engine since the first Penumbra game — add it to the short list.