Tunnel Warfare

Overview

Tunnel warfare is one of the two defining asymmetric mechanics of Hell Let Loose: Vietnam — available exclusively to the North Vietnamese Army. NVA forces can construct extensive tunnel networks during a match, enabling surprise attacks from unexpected positions, hidden spawn infrastructure, and underground repositioning that US forces cannot detect or intercept above ground.

This single mechanic gives the NVA a fundamentally different defensive and offensive playbook from US forces — one rooted in concealment, indirect approach, and the ability to strike from positions the enemy believes to be secure.

Confirmed Tunnel Mechanics

The following values are documented from the Hell Let Loose: Vietnam closed beta:

How Tunnels Differ from Garrisons

Understanding the difference between NVA tunnels and standard Garrisons is key to playing either faction effectively:

The free supply cost and neutral territory placement are the tunnel’s biggest advantages. A Garrison requires supplies, coordination with a Support player, and cannot be placed forward of the neutral zone — tunnels have none of these constraints.

Tactical Implications

Tunnels reshape how the NVA fight at every level:

Offensive Use

• Deep insertions: tunnel exits placed in neutral or even enemy-adjacent territory allow NVA squads to appear far forward of where US forces expect them, bypassing the contested frontline entirely
• Surprise attacks: the NVA’s confirmed ability to gain the upper hand with surprise attacks is directly enabled by tunnel exits in unexpected positions
• Post-capture persistence: even after a point is “cleared” by US forces, tunnel exits in the area keep the NVA threat alive — squads can re-emerge behind the new US position

Defensive Use

• Hidden spawn infrastructure: tunnel exits on defence provide spawn points that are harder for US forces to find and destroy than surface-level Garrisons
• Counter-attack corridors: tunnels on the flanks of a defended position allow rapid counter-attacks when the US pushes — NVA forces can appear on the attacker’s flank or rear as they push through
• Armour synergy: tunnel exits placed behind US Anti-Tank positions allow NVA infantry to eliminate AT threats before the T-54 pushes — clearing the way without exposing the tank

NVA Tunnel vs US Garrison — Asymmetric Balance

HLL: Vietnam is built on deliberate asymmetry. The US has helicopters and air mobility; the NVA has tunnel networks and underground spawn infrastructure. Neither side is simply a reskin of the other — they fight with genuinely different tools.

A US team that doesn’t adapt to tunnel warfare will be surprised repeatedly. An NVA team that builds tunnels carelessly — too few, too obvious, too close to known US positions — wastes the faction’s most powerful structural advantage.

Likely Counter-Play (US Forces)

Specific counter-tunnel mechanics are not yet fully detailed. Based on confirmed and inferred design:

• Engineers can potentially destroy tunnel entrances/exits
• US forces should check buildings, treelines, and terrain features behind their frontline for tunnel exits
• Helicopter overwatch from above can help spot NVA movement around suspected tunnel areas
• Clearing a point doesn’t mean clearing the tunnel network — always check for exits in and around captured positions

Historical Context

The real-world inspiration is the Cu Chi tunnel system — hundreds of kilometres of underground passages used by NVA and Viet Cong forces for movement, supply, command, and ambush. The Cu Chi tunnels ran beneath US firebases and proved nearly impossible to fully eliminate. HLL: Vietnam translates this historical asymmetry directly into gameplay: an opponent who can be everywhere, who leaves no visible footprint above ground, and who strikes from positions you thought you controlled.

Placement Strategy

For maximum effect:

• Place your first tunnel early, before the fight reaches the area — an undiscovered tunnel in neutral territory is a match-long asset
• Spread tunnels across multiple network links rather than clustering them — if the US finds one exit, they shouldn’t find all of them
• Place in cover: treelines, vegetation, inside structures. Never on open ground
• Coordinate with your Officer — tunnels placed behind the next objective before the push begins are far more valuable than tunnels placed after the push stalls
• Save tunnel placements for positions that will remain relevant — a tunnel in an area the team abandons is a wasted slot of your 15-tunnel team cap

Related

• Pilot (Helicopter) — the US asymmetric counter to NVA tunnels
• Engineer — likely role for US counter-tunnel demolition
• Spotter — the only class that can place a spawn in locked enemy territory (surface equivalent of a deep tunnel exit)
• Đắk Tô Airfield — highland terrain where ridge reverse-slopes make ideal tunnel placement ground