Block Bastion

Overview

Block Bastion is a 3D tower-defense game. Enemies advance along a canyon toward your Command Core; towers you place acquire and fire on their own. The campaign is 60 waves in groups of three, making 20 levels.

The Command Core starts each campaign with 30 hit points. Every enemy that reaches it removes 1 to 4, depending on the unit. Clearing a level restores 3 HP, capped at the starting maximum. The campaign ends when the Core reaches 0.

The build grid

Placement is on a grid of 0.5-metre cells, 27 by 51. Each buildable occupies a square footprint:

• Walls and towers — 2×2 cells
• Mine — 3×3 cells
• Factory and Lab — 4×4 cells

Only the corridor floor and the low shoulder band beside it are legal ground. Two hard caps apply: 60 walls and 32 buildings, where buildings means towers, Mines, Factory and Lab — walls are not counted against it.

Enemy pathing

Ground units follow the gradient of a Dijkstra distance field computed from the Core across the corridor, so walls re-route them rather than being obstacles on a fixed track. A placement that would completely block the spawn from the Core is rejected.

A tower can be mounted on top of a wall; mounted turrets render at reduced scale. Air units do not use the ground field and are unaffected by walls.

Towers

Values are cost, range in metres, shots per second, damage per shot, and targeting.

• Cannon — 70, range 6.5, 1.3/s, 22 damage, ground only. Unlocks at level 1.
• AA Gun — 90, range 7.5, 3.0/s, 10 damage, air only. Unlocks at level 1.
• Missile — 140, range 8.0, 0.7/s, 40 damage, 2.2 m splash, air and ground. Level 3, and requires a Factory.
• Tesla — 120, range 5.5, 1.1/s, 7 damage, ground only; slows to 50% speed for 2.0 s. Level 5, and requires a Lab.
• EMP — 110, range 6.5, 0.9/s, 6 damage, air only; slows to 45% speed for 2.5 s. Level 4, and requires a Lab.

AA and EMP cannot hit ground units; Cannon and Tesla cannot hit air. Only the Missile hits both.

Structures

• Wall — 8 coins. Blocks ground movement. Level 1.
• Mine — 90 coins. Pays +4 coins every 5 seconds. Level 2.
• Factory — 130 coins. Unlocks Missile towers. Level 3.
• Lab — 150 coins. Unlocks Tesla, EMP and all tower upgrades. Level 4.

A card is locked if its unlock level is above the current campaign level, or if its required structure has not been built.

Economy and upgrades

You start with 220 coins. Kill bounties scale with the wave index as base × (1 + 0.05w). Clearing a wave pays 20 + 6×n coins, where n is the number of waves completed.

Towers upgrade to level 5. Each level above the first multiplies damage by 1 + 0.55×(level−1), range by 1 + 0.08×(level−1) and fire rate by 1 + 0.18×(level−1). An upgrade costs base cost × 0.9 × current level. Selling returns 70% of everything invested in that building.

Enemies

Seventeen unit types across three chassis. Values are health, speed, bounty and Core damage.

• Light, ground — Scout 45/2.4/6/1, Raider 40/3.4/8/1, Viper 55/3.0/9/1, Phantom 35/4.4/11/1, Bomber 65/3.0/10/3
• Heavy, ground — Blitz 90/2.7/14/2, Truck 130/1.7/15/2, Warden 200/1.5/20/2, Armored 280/1.3/26/3, Juggernaut 480/1.0/45/4
• Air — Wasp 45/3.2/9/1, Jet 40/4.3/14/1, Specter 55/3.0/13/1, Hornet 60/2.6/11/1, Drone 70/2.0/10/1, Raptor 85/3.6/18/2, Gunship 260/1.2/38/3

Health scales by wave as 1 + 0.045w + 0.0008w². Speed scales as 1 + 0.005w, capped at 1.25×. Bounty scaling is slower than health scaling.

Return fire from wave 21

From wave index 21 onward, five unit types attack your buildings: Warden 4 damage, Armored 6, Gunship 7, Juggernaut 10, Raptor 4, once every 1.25 seconds. They target the nearest building within 3.2 m for ground units, 4.2 m for air.

Walls are excluded and cannot be damaged. Any other building reduced to 0 HP is destroyed and its cells are freed for rebuilding. The level dialog before wave 21 displays a warning that heavy enemies now return fire.

Controls

Select a build card from the bottom bar, then double-tap a highlighted cell to place it. Tap a placed building to open the upgrade and sell panel. Press Send Wave to start the next wave; the game holds in a building phase between waves. A four-step tutorial covers the spawn point, placing a Cannon, placing a wall, and sending the wave. Mouse or touch, landscape.