Thornline TD is a maze tower defense strategy game for PC that puts players in control of building winding paths with towers to slow and eliminate waves of enemies. In this indie title currently approaching Early Access, the core loop revolves around constructing defensive mazes where towers serve as both damage dealers and barriers, forcing enemies along longer routes through concentrated fire zones.
Gameplay
The central mechanic requires players to place towers that double as walls. Enemies follow the only available path through the maze, and towers cannot be positioned in ways that fully block progress. This setup rewards careful planning to extend enemy travel time while routing them past the most powerful defenses. Eight distinct towers become available progressively: Arrow, Cannon, Frost, Poison, Lightning, Catapult, Flamethrower, and Sniper. Each supports two upgrades that increase strength without altering core function. Armor on enemies reduces incoming damage by a fixed amount per hit, making heavier towers like the Cannon more effective against armored foes than lighter ones such as the Arrow. Success depends on adapting placements to each wave's composition and enemy behaviors.
Special enemies add variety across the campaign. The Wrecker steals gold on contact, the Scarab's armor weakens with successive hits, the Boar accelerates when damaged, the Ghoul regenerates health when untargeted, and the Knight splits into beetles upon defeat. Nine bosses appear at the end of most levels, culminating in the Thorn King at level fifty.
Game Modes
Two primary ways to play exist. Solo mode offers fifty levels spread across ten worlds. The first world follows standard rules, while each subsequent world introduces a unique twist, such as waves emerging midway through the path on the Sunbarrens, bosses entering from the keep and traversing the maze backward on the Frostline, doubled enemy counts with halved health on every other wave in the Saltmarsh, or slain enemies reviving in the Barrows. The same level layout repeats on retries, allowing incremental adjustments after close defeats. After level fifty, worlds cycle again with increased difficulty. A relic choice appears every fourth round, offering either a temporary power or gold instead. Three stars plus a crown are achievable per level, with stars unlocking permanent upgrades like starting gold bonuses, tower improvements, or better interest rates.
Multiplayer supports up to eight participants, each managing an independent maze. Between waves, players allocate gold between tower construction for defense or purchasing units to dispatch into opponents' lanes. Units sent this way permanently increase the sender's income, creating an ongoing economic trade-off between offense and defense. The last player with an intact keep wins. Friends can join directly, with bots filling remaining slots, or a full skirmish against seven bots can be played offline.
Progression and Features
Permanent upgrades purchased with stars carry across solo levels, encouraging repeated attempts to optimize star collection. Relics provide run-specific advantages that players must weigh against immediate gold gains. The full set of towers, levels, worlds, and multiplayer features is included from the start with no additional purchases required. Solo content functions completely offline, while online matches require an internet connection only for that mode.
Is It Worth Playing?
Thornline TD targets players who enjoy deliberate, path-building tower defense combined with light economic decision-making in multiplayer. The solo campaign delivers a structured challenge with escalating world rules and enemy variety that demands adaptation rather than repetition. Multiplayer adds a competitive layer where sending units creates direct interaction without requiring constant real-time coordination. As an upcoming Early Access release from a solo developer, the game is described as functionally complete in its core systems, with the Early Access period focused on balance adjustments and additional relics based on community input. Those seeking a one-time purchase strategy experience with both offline solo depth and optional online competition will find the described mechanics align closely with classic maze defense principles updated by persistent income incentives and world-specific modifiers. Availability on PC makes it accessible for those comfortable with keyboard and mouse controls in a grid-based environment.