Halflife 2 's steam engine was so gorgeous they actuallt made a very small episode called lost coast, just to show it off. It was a brag fest. Just like the original game they went to town on it.
It still looks great and yes I own them all. Every couple of months I plug some combine soldiers or head crabs with a cross bow just to keep my eye in.
The escapades in the Antlion Nest were graphically stunning.
The views from underneath the bridge whilst infiltrating it, the scenery whilst crossing country in the car, the coastline whilst using the vw beach buggy, the river and lakeland from the Airboat,esp whilst searching the river banks, the river beds and forest from the V8 muscle car, the list is endless.
https://www.google.co.uk/search?q=halflife+2+water+vehicles&espv=2&biw=1097&bih=534&tbm=isch&imgil=A579U0fOyhFyEM%253A%253B3cTh-7sTxvxA0M%253Bhttp%25253A%25252F%25252Fhalf-life.wikia.com%25252Fwiki%25252FAirboat&source=iu&pf=m&fir=A579U0fOyhFyEM%253A%252C3cTh-7sTxvxA0M%252C_&usg=__y818VVtFAcVKJnq99_NAo3kmb30%3D&dpr=1.75&ved=0CDcQyjc&ei=IJ1NVaz4MIn5UtjPgZAI#imgrc=jO3NOIBuZJakLM%253A%3BkQYYnfFXe2cCqM%3Bhttps%253A%252F%252Fgamemaster5436.files.wordpress.com%252F2007%252F06%252Fhalflife-4.jpg%3Bhttps%253A%252F%252Fgamemaster5436.wordpress.com%252Fhalf-life-2%252F%3B1280%3B1024
https://www.google.co.uk/search?q=halflife+2+water+vehicles&espv=2&biw=1097&bih=534&tbm=isch&imgil=A579U0fOyhFyEM%253A%253B3cTh-7sTxvxA0M%253Bhttp%25253A%25252F%25252Fhalf-life.wikia.com%25252Fwiki%25252FAirboat&source=iu&pf=m&fir=A579U0fOyhFyEM%253A%252C3cTh-7sTxvxA0M%252C_&usg=__y818VVtFAcVKJnq99_NAo3kmb30%3D&dpr=1.75&ved=0CDcQyjc&ei=IJ1NVaz4MIn5UtjPgZAI#imgrc=44pWVgCCZqPS_M%253A%3BYEm3sYCR9z-hVM%3Bhttp%253A%252F%252Foi40.tinypic.com%252F9u9oqa.jpg%3Bhttp%253A%252F%252F4playernetwork.com%252Fblog%252F2013%252F08%252Fso-i-played-half-life-2-for-the-first-time%252F%3B620%3B300
https://www.google.co.uk/search?q=halflife+2+water+vehicles&espv=2&biw=1097&bih=534&tbm=isch&imgil=A579U0fOyhFyEM%253A%253B3cTh-7sTxvxA0M%253Bhttp%25253A%25252F%25252Fhalf-life.wikia.com%25252Fwiki%25252FAirboat&source=iu&pf=m&fir=A579U0fOyhFyEM%253A%252C3cTh-7sTxvxA0M%252C_&usg=__y818VVtFAcVKJnq99_NAo3kmb30%3D&dpr=1.75&ved=0CDcQyjc&ei=IJ1NVaz4MIn5UtjPgZAI#imgdii=jO3NOIBuZJakLM%3A%3BjO3NOIBuZJakLM%3A%3Bqotxf02s6U5-FM%3A&imgrc=jO3NOIBuZJakLM%253A%3BkQYYnfFXe2cCqM%3Bhttps%253A%252F%252Fgamemaster5436.files.wordpress.com%252F2007%252F06%252Fhalflife-4.jpg%3Bhttps%253A%252F%252Fgamemaster5436.wordpress.com%252Fhalf-life-2%252F%3B1280%3B1024
I have never seen anything so well optimised or with anywhere near as much effort to be honest. Its a shame they gave up making games.