Hi, this is a very minor thing but maybe it’s something you want to fix nevertheless for consistency.
The periodic tables at several walls feature the elements Darmstadtium (110 Ds) and Röntgenium (111 Rg).
Those elements have been named only very recently in 2003 and 2004.
Prior to this, they got the interim names Ununnilium (Uun) and Unununium (Uuu).
According to this timeline https://www.members.shaw.ca/halflifestory/timeline.htm, HL1 takes place in 2000.
Not sure how correct this page is though.
P.S. The game is even surpassing my very high expectations.
Thank you, it was definitely worth the wait every single year! 
