What's that goop over on the right-hand side? The surrounding buildings where humans live are looking real fancy too, though that's more 12 years of technological progress at Valve than better living conditions in City 17. The Combine Citadel is still under construction at the time of HL: Alyx but already dominates the skyline and certainly is a sight (click screens to embiggen, obvs):
It's been twelve years since the last game in the series and this one takes the action to Valve's Source 2 engine, so if you squint real hard it's almost like you're looking at a remake of Half-Life 2 too. The VR exclusive (which Valve tell us really does need to be VR, else 'for all intents and purposes it would be an entirely different game') is set a few years before the return of Gordon Freeman and stars Alyx Vance as she helps build resistance against City 17's alien occupiers. Now Valve have formally announced the upcoming Half-Life: Alyx, we can pore and coo over its first screenshots in shiny 4K resolution.
