Outrageously ambitious (opens in new tab) Half-Life 2 megamod Entropy: Zero 2 is out, letting you experience a campaign in the boots of the Combine bad guys. You're the Bad Cop, protagonist and alien overlord collaborator, and your job is to tail Gordon Freeman through Nova Prospekt prison before taking a journey to track down resistance fighter Dr. Judith Mossman in a snowy northern facility.
If you're a Half-Life 2 player I'm sure you know how that goes. Either way, you'll play through a shockingly detailed campaign, fully voiced, fully choreographed, that takes something like 7-10 hours to beat. Frankly, it's on the quality of many games we considered big to mid-budget 20-some years ago.
Oh, and there's Portal shenanigans afoot and an Aperture science facility involved. You get a turret buddy. Naturally, the Portal turret buddy is named Wilson, because everyone who watched Tom Hanks in Castaway has had that indelible concept scratched upon their brain.
Entropy: Zero 2's most impressive aspect is definitely its overhauls and new additions to the tried-and-true Half-Life 2 combat formula. There are new enemies, weapons, and effects. There's a grenade that sends everything caught in it to Xen and spits out weird Xen monsters in exchange. You can command teams of Combine, deploy manhack drones, and generally act like a person who sold their entire species out for some alien overlord perks.
Entropy: Zero 2 is a sequel, technically, to Breadman's solo mod Entropy: Zero, one of the best-received and better HL2 mods of all time. This one's on a whole other scale compared to that first one, with a bigger team and a much bigger scope. I mean they made it so you could drive those APCs from Half-Life 2. I love it.