Mods / Underground

• LLEVITATION (Part 1)by FMPONELEVITATION is a community campaign featuring: New story (3-4 hours in length) New voicelines New character animations Eight challenging levels Subscribe: This is Part 1 of 5. Subscribe to LEVITATION's Workshop Collection. Enable all parts via Manage Add-ons, then play Part 1 and enjoy -- the leve...115.4k downloadsupdated 4 y ago
• LLEVITATION (Part 2)by FMPONELEVITATION is a community campaign featuring: New story (3-4 hours in length) New voicelines New character animations Eight challenging levels Subscribe: This is Part 2 of 5. Subscribe to LEVITATION's Workshop Collection. Enable all parts via Manage Add-ons, then play Part 1 and enjoy -- the leve...101.1k downloadsupdated 4 y ago
• LLEVITATION (Part 3)by FMPONELEVITATION is a community campaign featuring: New story (3-4 hours in length) New voicelines New character animations Eight challenging levels Subscribe: This is Part 3 of 5. Subscribe to LEVITATION's Workshop Collection. Enable all parts via Manage Add-ons, then play Part 1 and enjoy -- the leve...98.4k downloadsupdated 4 y ago
• LLEVITATION (Part 4)by FMPONELEVITATION is a community campaign featuring: New story (3-4 hours in length) New voicelines New character animations Eight challenging levels Subscribe: This is Part 4 of 5. Subscribe to LEVITATION's Workshop Collection. Enable all parts via Manage Add-ons, then play Part 1 and enjoy -- the leve...98.2k downloadsupdated 4 y ago
• LLEVITATION (Part 5)by FMPONELEVITATION is a community campaign featuring: New story (3-4 hours in length) New voicelines New character animations Eight challenging levels Subscribe: This is Part 5 of 5. Subscribe to LEVITATION's Workshop Collection. Enable all parts via Manage Add-ons, then play Part 1 and enjoy -- the leve...97.0k downloadsupdated 4 y ago
• CC17YSCAPE ([OLD VERSION] [Check description!])by PrivateHorseLegsIMPORTANT NOTE: This is an old version of the mod. If you want to play the updated version, download the mod here: ------------------ Taking place in City 17 during events between Half-Life: Alyx and Half-Life 2, you are a citizen who was just now captured by the Combine and and kept prison in a...91.7k downloadsupdated 6 y ago
• MMine Break - Chapter 1by SadlyItsBradleyPart 2: From the creator of "Crash Course," Here is a whole new project with a larger line of sight. Story The Metro Police did a surprise inspection of your sector and found that your building's residents had ties to a growing resistance. Eviction, or rather, escape - was necessary. In order to...74.1k downloadsupdated 6 y ago
• CCrash Courseby SadlyItsBradleyStory You are an underground Biologist studying Xen creatures for purpose in helping the resistance. After a recent transgression above ground, it seems the Combine have found out about your deeds and are at your door - trying to stop it. Your objective is to escape the war torn area filled with...64.4k downloadsupdated 6 y ago
• TThe Undertowby DorminYou play as Alyx, tasked with delivering a mysterious briefcase to the owner of an underground night club, upon arriving you realize this deal might not be so straight forward... ⠀⠀⠀⠀⠀⠀⠀⠀ Expected Playtime: 50min - 1hr Features: Full-fledged Story with Voice Acting Custom Sounds, Assets, and Game...46.5k downloadsupdated 4 y ago
• GGoon Squadby G KafYou and your Combine squad are trapped in a quarantined sewer system. Find a way out and escape! First place winner of the Vaultmaps Trapped competition! This is a standalone release that polishes the original contest map. Have fun! I'd love to hear your thoughts on the map in the comments! Donat...39.1k downloadsupdated 6 y ago
• MMine Break - Chapter 2by SadlyItsBradleyFrom the creator of "Crash Course" and MineBreak part 1. Here is a the continuation of the multi-level campaign that has got some people talking. Story After reaching what seemed to be the end of the Mine in chapter 1, you had a quick run in with the combine that caused the final tunnel to cave i...36.7k downloadsupdated 6 y ago
• CC17YSCAPE Update (Part 2/2)by PrivateHorseLegs1ST NOTE (VERY IMPORTANT!!!!!): Before playing this mod, make sure to have both Part 1 and Part 2 installed AND enabled! The map transition between the two mods will not work if not followed correctly. 2ND NOTE: Please check the "Change Notes" tab to see what has been updated for the mod. 3RD NOT...34.6k downloadsupdated 3 y ago
• CC17YSCAPE Update (Part 1/2)by PrivateHorseLegs1ST NOTE (VERY IMPORTANT!!!!!): Before playing this mod, make sure to have both Part 1 and Part 2 installed AND enabled! The map transition between the two mods will not work if not followed correctly. 2ND NOTE: Please check the "Change Notes" tab to see what has been updated for the mod. 3RD NOT...34.4k downloadsupdated 3 y ago
• AAlyx Bond - Runway (Demo)by ChimonaheheYour time has finally come, Agent Alyx Bond. Play the first chapter “Complex” in an experience that is unlike any other as you enter into Soviet Combine territory. Alyx Bond: Runway is the infusion of over 21 developers who worked hard to bring out the best in Source 2. Featuring custom composed...23.2k downloadsupdated 5 y ago
• GGarage Masterby GvaradosUnlock the full potential of the garage. Become the GARAGE MASTER! This is a 15-ish minute campaign map. I made this in 3 days, before the tools released. Follow my twitter or join my discord for more maps!21.1k downloadsupdated 7 y ago
• HHalf-Life: Zhepticsby BrainstormHalf-Life: Zheptics You are Alyx, who was sent on a mission with her brother for the resistance. As you explore the forgotten research facility 'Zheptics' from Black Mesa, things start to spiral out of control, culminating in a finale with everything at stake. Expect classic campaign gameplay of...17.5k downloadsupdated 3 y ago
• PPyromantic Gatekeeperby JWIt's time to leave City17. Alyx gets help from resistance member Ivan who is also quite cunning. Use his bombs and traps to obliterate your foes so you can rejoin with your father in Black Mesa East. About gameplay: - new explosive traps that can be dealt with gravity gloves - new bombs that can...16.5k downloadsupdated 6 y ago
• FFrom Here To There (Part 1 of 3)by ChiueyCreated by Chiuey - OPEN BETA *This campaign requires physical climbing of in-game ladders and objects. Start the campaign with the map "T-Day_Intro" Collect 80 total resin or more for a Bonus You must ENABLE the 3 addon parts and 4 REMADE ASSETS parts to play. ___________________________________...16.3k downloadsupdated 4 y ago
• FFrom Here To There (Part 2 of 3)by ChiueyThis is the REQUIRED (Part 2 of 3) for the From Here To There Add-on.16.1k downloadsupdated 4 y ago
• FFrom Here To There (Part 3 of 3)by ChiueyThis is the REQUIRED (Part 3 of 3) for the From Here To There Add-on.16.1k downloadsupdated 4 y ago
• CCoD Zombies VRby PancakesIt's a Call of Duty Zombies style game mode in HL:A, See how long you can survive! I've unfortunately lost the source to this mod, so there will not be any more updates List of Features: 4 Maps - House, Train, Bones and Snow, with dark modes Auto healing Custom Settings Doors to buy Drops Perks P...15.5k downloadsupdated 4 y ago
• ||Portal 2| The Courtesy Callby 76561198882852673start with map sp_a1_intro1 MOTION SICKNESS WARNING: There are fast-paced sequences. This experience was designed with Smooth Locomotion in mind. There may be issues if you use launch options that increase the default smooth locomotion speed. If you want to get in touch with me or follow developm...12.6k downloadsupdated 11 mo ago
• TThe Courtesy Call - Remaining Mapsby 76561198882852673These are the maps that didn't fit within the 2GB limit for the Main Addon.12.2k downloadsupdated 11 mo ago
• TThe Courtesy Call - Required Assets 1/3by 76561198882852673This required pack contains Materials for my port of chapter 1 of Portal 2. Main Addon12.0k downloadsupdated 11 mo ago
• TThe Courtesy Call - Required Assets 3/3by 76561198882852673This required pack contains Models/Sounds for my port of chapter 1 of Portal 2. Main Addon12.0k downloadsupdated 11 mo ago
• TThe Courtesy Call - Required Assets 2/3by 76561198882852673This required pack contains more Materials for my port of chapter 1 of Portal 2. Main Addon12.0k downloadsupdated 11 mo ago
• CCompliance Unconfirmed [PART 1]by ProbablyOKVersion 1.1 You do not need PART 2 to play this addon. Simply subscribe to this addon! Subscribe to Part 2 You are initiate 14, a resistance member in training, and you have been tasked with locating Initiate 13, who suddenly went radio silent 24 hours ago. However, as you delve deeper into the d...11.4k downloadsupdated 6 y ago
• MMapping Contest - Combine Presence (ADDON 1 of 2)by GvaradosThis is a compilation addon of an old contest. I recommend searching the workshop to find new versions each map :) ADDON PART 2: Half-Life: Alyx Modding Hub & Half-Life Discord Mapping Contest Information This is the mega addon for the first HLA mapping contest. It was hosted by Gvarados in colla...10.4k downloadsupdated 6 y ago
• MMapping Contest - Combine Presence (ADDON 2 of 2)by GvaradosThis is a compilation addon of an old contest. I recommend searching the workshop to find new versions each map :) ADDON PART 1: Half-Life: Alyx Modding Hub & Half-Life Discord Mapping Contest Information This is the mega addon for the first HLA mapping contest. It was hosted by Gvarados in colla...9.9k downloadsupdated 6 y ago
• OOPERATORby CementStairsThere is no point in trying to disobey. It is time. Again... Features Hardcore close-quarter combat Feverish brutalist geometry Dismemberment of limbs for Combine Grunts! Designed around Smooth Locomotion first! Horror themes with bio-mechanical inspiration Appropriately sickly color palette And...9.8k downloadsupdated 4 y ago
• CCompliance Unconfirmed [PART 2]by ProbablyOKVersion 1.0 It is recommended you play PART 1 before this experience. PART 1 does not need to be installed for this addon to work. Subscribe to Part 1 Initiate 14’s mission continues. After the events of PART 1, it is clear that your mission has become far more dire. As you approach your final ob...9.5k downloadsupdated 5 y ago
• PProspekt Attritionby jonoPorterReturn to Nova Prospekt with Prospekt Attrition! Rumors are going around that the Combine are re-purposing an old Russian gulag and are turning into something way worse. Desperate for more information Alyx travels to said facility to take a closer look and gain some insight into what the Combine...9.4k downloadsupdated 6 y ago
• [[p1] Test_Chamber_01 & Test_chamber_02 DuelPackby TheBoxTrotTwo Maps in one scientific package the first two maps from portal 1 more is in the works >:) Featuring Working Portals by Adesi full Glados dialogue destructible cameras Flushable Toilets !!! working count down (seems to not be working but works in my local copy so idk) Credits: Assets such as fi...9.2k downloadsupdated 5 y ago
• SStorm Drainby SmurftYoursIntro: Russell - Alyx, come in. Hey Alyx! Oh, there you are. Can you hear me? I found a bunch of subterranean map data for your area of the city! Alyx - No shortcut? Russell - Yeah, that IS the shortcut... Story: Do you have what it takes to navigate the Storm Drain and get yourself on the next t...8.9k downloadsupdated 4 y ago
• [[P2] Sp_a2_triple_laserby TheBoxTrotSp_a2_triple_laser from Portal 2 remade in Source 2 with working game mechanics hopefully the first of many portal 2 remade levels to come Featuring working arrival and exit elevators Muisc and Glados audio Working Lasers and Cubes Hidden Puzzle Solver Button Important Note this Chamber is imposs...8.2k downloadsupdated 5 y ago
• EExtra-Ordinary Valueby dmtdeadman-First map is You're Awake You awaken in an abandoned hotel after being in a deep coma for over a year. During that time the 7 hour war has taken place, and the combine are slowly gaining control over the Earth. Obviously you want to find out if your family is safe and where they are. Upon leavin...7.5k downloadsupdated 4 y ago
• PPortal's Test Chamber 00by 5FB5Hello and, again, welcome to the Aperture Science computer-aided enrichment center. Features: - Working buttons; - Cubes have physics; - Working elevator; - Signs with animations; Some issues I'll fix in future updates. My Twitter: LitTlE GiRLl, iTS okAY, YOour PaIN Is iGNrOeD By A LiTTlE piLLl7.3k downloadsupdated 6 y ago
• BBuckshot Bugsby Soup MarioA shotgun only combat map where you're forced to both be attentive and aggressive to survive. Every shot matters, and if you're not observant you may have to scavenge while you're being attacked. Fight to the surface, get to the train, and make it home safely. Features -A fully custom soundtrack...7.1k downloadsupdated 3 y ago
• [[P2] Sp_a2_coreby TheBoxTrotSp_a2_core, experience GLaDOS's dethroning and betrayal of your companion Wheatley in amazing VR This is now the most complex map to recreate, as was the last. having to recreate all the scenes and animations manually while trying to handle the usual everything is broken thing Featuring Wheatley...6.3k downloadsupdated 5 y ago
• BBackyard Restingby jonoPorterBackyard Resting Alyx is hiding out in a small shack somewhere in City 17, taking a break from her usual activities until she gets violently interrupted. Features: 20-30 minutes of playtime Hidden loot to be found Somewhat challenging combat A secret cat Buy me a coffee and support my HL:A moddin...5.7k downloadsupdated 6 y ago
• DDecay Chainby 1600 frogsA vanilla-style map in the heart of City 17 Just prior to the events of Half-Life: Alyx, the resistance is on the verge of a major heist, the theft of a Combine reactor. The Citadel's monitoring and security systems would make such a heist impossible were it not for a flaw Russel has identified;...5.6k downloadsupdated 17 mo ago
• CCave Explorationby ImDrinking_Coca1st place in the first Vaultmaps contest! The Combine found a powerful source of energy in a desertic cave and they are going to use it against the resistance. You need to make your way deep down the Xen infested cave and steal that battery from them. A few surprises are waiting for you, so you b...5.4k downloadsupdated 6 y ago
• RResistance Revenge 2by 76561198344122478my epic website: If you want to know how I made this map or any of my other maps, then click on the google drive link below. I have any of my addons uploaded there. Feel free to copy ideas or anything else and have fun making your own maps or feel free to use them for SFM animations! This is the...5.3k downloadsupdated 5 y ago
• RResistance Revengeby 76561198344122478my epic website: This is the 3rd map that I have made for hl:a and it was probably the biggest map I will ever make. It's 1 - 1.5 hours long, has 109 Resin to collect, and features a mix of puzzles combat, and a tiny bit of horror. If you are stuck at any point you can always dm me, write in the...5.2k downloadsupdated 4 y ago
• [[P2] Sp_a1_wakeupby TheBoxTrotSp_a1_wakeup experience glados's reawakening in amazing VR this was probably the most complex map to recreate. having to recreate all the scenes and animations manually while trying to handle the usual everything is broken thing but the results were def worth it this map has a lot of firsts for m...4.9k downloadsupdated 5 y ago
• RResistance Revenge 3: The Finaleby 76561198344122478my epic website: If you want to know how I made this map or any of my other maps, then click on the google drive link below. I have any of my addons uploaded there. Feel free to copy ideas or anything else and have fun making your own maps or feel free to use them for SFM animations! This is the...4.5k downloadsupdated 4 y ago
• TTheatre Maniacby HerneeriusA pistol-only map where you are trapped in a theatre and have to escape. This is my first map and I hope you enjoy playing it! I would appreciate any feedback I get.4.3k downloadsupdated 3 y ago
• [[P2] Sp_a3_00by TheBoxTrota complete port of sp_a3_00 or The Fall from Portal 2 this map was an interesting map to port as it contained a lot of things that i had to remake from scratch as a lot of the features it used are not available in source 2 such as the depth signs features Talking Potato?!?! long hole and a bottom...4.1k downloadsupdated 5 y ago

128 underground mods, most downloaded first. Each one has its own page here with what it needs to run and where its author publishes it; the files themselves stay with the author and are never re-hosted on this site.