Retusa

Retusa is a tier 1 naval support unit that combines a mobile repair point with a short-range offensive capability. It appears exclusively on water and supports allied vessels and amphibious forces by repairing units and damaged buildings while also firing homing torpedoes and short lasers at nearby enemy targets. Retusa fills a frontline support niche within Mindustry’s naval unit lineup, trading heavy durability and direct damage for strong sustain and utility.

Retusa’s primary function is healing. Its central repair beam restores 45 HP per second to allied units within 15 tiles, and its repair beam can heal blocks as well as units. This high repair rate makes it one of the fastest-building/healing tier 1 units when scaled (notably at 150% it surpasses many other low-tier units in build speed). Because it moves on water, Retusa is used to keep naval task forces and raiding squadrons topped up during engagements.

Offensively, Retusa fires two short laser weapons and a water-bound torpedo weapon. The lasers fire at 2 × 1.36 shots/sec, deal 12 damage per bolt, and provide 5.5% repair to blocks on hit. The torpedoes are homing water-only projectiles with the following notable properties: 2 shots/sec, 40 area damage over a ~4.0 tile radius (after later updates), homing power 0.05, projectile speed ≈5.25 tiles/sec, and a limited lifespan. Torpedoes were reworked from proximity sea mines into homing torpedoes in earlier updates and later gained increased area damage and range; they do not travel on land and detonate or are ineffective when crossing solid terrain. The Retusa’s laser armament allows it to engage air targets (lasers only), while torpedoes are restricted to sea targets.

Retusa’s AI and behavior are tuned for close support. It was originally added with a proximity mine mechanic and a “HugAI” behavior, but subsequent updates changed its behavior to the default unit AI and altered weapons to better fit naval combat. Build cost and requirements were adjusted across versions (Metaglass cost was removed from the Naval Factory recipe in later builds, and factory build time was reduced). A command limit was present early on and later removed.

Practical notes and strategy:

• Retusa excels as a mobile repair platform for naval formations; keep it near damaged allies so its 45 HP/s repair beam can maximize uptime.
• Position allied buildings and units at least two tiles inland from the coast to negate torpedo effectiveness; torpedoes detonate prematurely on solid land and will fail to threaten inland targets.
• High burst-damage turrets that can reduce repair time are effective counters; the Lancer is explicitly strong because it can kill Retusa in two hits in typical scenarios.
• Retusa’s lasers provide limited anti-air coverage; rely on the lasers rather than torpedoes when engaging flying units.
• Retusa is outclassed by some higher-tier support options in specific roles: Oxynoe’s overclock field and Cyerce’s twin repair points provide stronger or more flexible support at higher tiers.
• Early versions used sea mines that detonated on proximity; the current torpedo system homing and inaccuracy values (2°) make it suited to engaging nearby enemy ships rather than precise long-range strikes.

Trivia and development notes:

• The unit’s name is derived from the Retusidae family of small sea snails; all members of the support naval line are named after marine gastropods.
• In development previews Retusa had two repair-point guns instead of one.
• Across builds, the torpedo mechanics, area damage, projectile speed, homing, and lifespan have been rebalanced several times to tune its role alongside added laser weapons and changes to factory recipes and build times.