Play the prototype
Controls and unlocked abilities
Start at level 7 and build your own beam layout. This preview includes RGB prisms, mirror rotation during combat, a mobile turret, and the damage upgrades from earlier levels.
Instruction: Click inside the game first. B buys a mirror (20 coins); Q/E rotate it in 45° steps before placement. Left-click to place; right-click or Esc to cancel. Drag a mirror end to rotate freely; hold Shift to snap to 45°. Drag its centre between waves to move it. Move the turret with WASD or mouse dragging; Space starts the next wave. Undo mirror removes the latest mirror with a full refund; Retry level restarts; Levels / Pause opens level selection or pauses.
Unlocked: Prisms, mirror rotation during waves, and turret movement with the mouse or WASD.
This is an all-abilities preview; the full version includes a tutorial level. After trying level 7, choose New run to experience the full progression, or download the Windows Demo on itch.io.
Download the full Windows Demo on itch.io ↗Play in a new window ↗
Prototype progress
Refraction Defense is a Unity 2D puzzle tower-defense prototype built in C#. Seven fixed levels connect mirror placement, enemy waves, an economy, and upgrade choices. The playable loop includes enemy health bars and damage numbers, base health, level selection, progression, defeat, and retry.
Each level begins with the cannon pointing away from useful road coverage. Placing and turning the first mirror creates an immediate, visible result. The challenge is to make a limited number of mirrors cover more of the enemy route.
Mirror controls and waves
Each mirror costs 20 coins and can be placed on or off the road. Between waves, drag its centre to move it or an end to rotate it; hold Shift to snap rotation to 45-degree angles. Placed mirrors normally lock their rotation and movement during a wave, while new mirrors can still be bought with kill rewards and placed. The battle-rotation upgrade unlocks rotation only.
The base starts with 3 health. Every enemy that reaches it removes 1 health, so choosing where to extend coverage matters. Before starting the next wave, the interface shows its enemy count and health.
The first wave introduces a workable arrangement. Later waves ask whether to extend that arrangement, redirect it between waves, or build around an upgrade.
Level design
Levels 1 and 2
Level 1 uses a folded route with mirror-position hints. Level 2 develops the rectangular arrangement from the original proposal. Position hints disappear after the first level, leaving players to work out their own coverage.
Level 6
Level 6 comes after players have learned the basic controls and unlocked two special upgrades. Its route remains easy to read, while nearby road sections create frequent opportunities for overlapping coverage and reuse of the same beam path. Players can combine the controls they have learned with their chosen upgrades to experiment with more complex optical layouts.
Level 7
Level 7 introduces mechanics for future levels with just two fixed mirrors and one beam absorber on the road, leaving the rest of the optical layout to the player. Fixed mirrors cannot be moved, rotated, or converted into prisms; beam absorbers terminate light on contact. Players can first observe these rules, then use the fixed reflection points or their unlocked turret movement, beam splitting, and battle rotation to work around the obstacle. Later development will combine these conditions gradually to create more complex layouts.
Level upgrades
Clearing levels 1, 2, and 4 offers a regular upgrade: +20% of base laser damage, +20 starting coins in later levels, or +1 maximum base health. Chosen effects carry into later levels.
After level 3, choose one special ability. After level 5, choose a second from the two remaining abilities. After level 6, claim the final ability and enter level 7 with all three available.
- Mobile turret: once unlocked, move directly with WASD or mouse dragging, during and between waves, without a placement-area restriction.
- RGB prism: mirrors split incoming white light into red, green, and blue beams, opening several directions of coverage.
- Battle rotation: rotate mirrors while enemies are moving, lifting the usual rotation lock.
The prototype uses seven authored levels with upgrades carried between them. Each ability changes the arrangements and interventions available to the player.
Laser damage and enemies
The main laser is white. With the prism upgrade, red, green, and blue beams can add their damage when they cover the same enemy. Multiple hits of the same color count only once, so ordinary mirrors cannot multiply damage by looping the same beam.
Later levels introduce larger, tougher red, green, and blue enemies. A beam matching a heavy enemy’s color deals 50% extra damage. The rule makes the direction of each colored branch matter, not just the total number of beams.
