Space Invaders · claude-haiku-5.5

I'll keep this efficient: write index.html in the current directory, test it briefly in a browser, then report back. First I should check what's in the working directory.

I'm starting with an empty directory, so I'll plan out the game structure before writing index.html: an 800x600 playfield, player movement at 300px/s with clamped bounds, and a bullet system with a cooldown around 400ms to limit fire rate.

For aliens, I'm sketching a 5x11 grid with step-based movement that speeds up as fewer remain, descending and reversing at edges, plus randomized firing capped at 3 active enemy bullets. I'm also designing destructible bunkers as cell grids that get cleared locally on impact, and working out collision rules including a brief invulnerability window after the player is hit.

I'm defining win/loss conditions—aliens reaching the player zone, lives hitting zero, or clearing all aliens—plus scoring per row type, hit feedback like particles and floating score text, and game states with restart controls. I'm also considering a debug hook via a window-exposed game object and tuning the alien step interval formula based on remaining alien count.

Now I'm working out alien movement speed and edge-descend behavior, procedural pixel-art sprites for the crab/squid/octopus aliens with alternating frames, and the player's danger line. I'm also laying out the four destructible bunkers as cell grids with arch-shaped cutouts, positioning them evenly across the canvas.

Defining bunker cell grid...

Now I'm figuring out collision detection between projectiles and bunker cells, clearing a small cluster of cells on impact and sampling multiple points along a bullet's path each frame to avoid tunneling through thin bunker walls.

For broader collisions, I'm checking alien bullets against the player with simple AABB overlap, and checking player bullets against each alive alien's rectangle since the alien count is small enough to make per-frame checks cheap. For enemy fire, I'll pick a random alive column to shoot from periodically, cap active enemy bullets at a few, and remove bullets once they scroll off the bottom of the screen.

On player hits, I'm decrementing lives, adding brief invulnerability with a flash effect, and triggering game over at zero lives, plus spawning explosion particles and floating score text on kills. I'm also defining the alien formation layout—five rows with squid/crab/octopus sprite types worth different points—along with pixel-art dimensions, spacing, and the threshold where aliens reaching the ground line ends the game.

Working out the formation's edge-detection logic for descending and reversing direction when aliens hit the screen bounds, then sketching 8x8 pixel sprite patterns for each alien type's two animation frames.

Still writing sprite patterns...

For rendering, I'll iterate through the alive grid and draw each pixel block with small filled rectangles per frame, which should be cheap enough without needing an offscreen cache. I'm also setting up particle-based explosions and defining bullet shapes—a simple rect for the player's shot and a zigzag-style enemy bullet.

I'm deciding on fire rate limits—capping the player to a couple of bullets on screen with a short cooldown—and setting up keyboard input handling for movement, shooting, and restart, plus a game loop with delta time capping and basic state fields for aliens, bullets, bunkers, and player status.

For the aliens, I'm computing each one's position from a formation offset plus row/column spacing, then figuring out the leftmost and rightmost alive columns to detect when the formation hits the screen edges and needs to step down and reverse direction. I'm tuning the step speed to scale with how many aliens remain alive, and checking the lowest alive row's position against the player's row to trigger a loss condition, then moving on to timing enemy bullet fire.

For enemy fire, I'm picking a random alive alien that's lowest in its column so shots look like they're coming from the front row, with bullets at 180px/s versus the player's 480px/s, then using rectangle overlap checks for bullet-alien collisions since the fast bullet speed means minimal risk of tunneling through. For bunker damage, I'm sampling points along the bullet's swept path each frame to detect when it enters a filled cell, destroying a cluster of cells and spawning particle effects on impact.

I'm clearing a cell plus its four orthogonal neighbors in a plus-shape when a bunker takes damage, which keeps the destruction pattern consistent and visually readable. For player-enemy bullet collisions I'm adding score based on alien row type, and for enemy bullets hitting the player I'm checking invulnerability first, then reducing lives, triggering explosion/flash effects, and ending the game if lives reach zero.

Win condition triggers when all aliens are cleared, and I want a floating "+30" style score feedback that fades over about 0.8 seconds. For the HUD I'm drawing score and lives directly on canvas plus adding an HTML control panel with a restart button below it, and exposing state through data attributes on the canvas element (status, score, lives) so it can be inspected externally.

Now I'm setting up the star field with roughly 80 randomly placed stars and sizing the canvas to 800x600 with responsive CSS scaling. Writing HTML boilerplate and base styles...

Still writing styles...

Now I'm defining the game constants -- grid dimensions for the alien formation, player size and movement speed, and the vertical zone marking where aliens become dangerous.

I'm also setting up the alien types with sprite frames and point values, bunker positions, and the overall game state structure including score, lives, projectiles, and particle effects for a classic Space Invaders-style setup.

Now I'm figuring out bunker collision detection: checking if a bullet's position falls within a bunker's bounds, converting that to a grid cell, and if filled, carving out a small cross-shaped hole plus spawning destruction particles. I'm also sweeping along the bullet's path to catch collisions even when the bullet moves fast between frames.

Then I'm writing the main update loop: handling player movement with clamping, firing cooldown logic that spawns player bullets with upward velocity, and planning how bullets get removed either by lifetime or collision.

For enemy collisions I'm checking rectangle overlap between bullets and alive aliens, awarding score and spawning explosion effects on hit, then sweeping the bullet path against bunker cells. For the formation stepping, I'm computing the alive aliens' bounding edges each tick, moving the group sideways until it hits a wall, then dropping it down and reversing direction, with step interval shrinking as fewer aliens remain alive. I also need a check for when the formation's lowest row reaches the defense zone to trigger game over, and I'm starting to plan the alien firing logic.

Now I'm working out particle and text update logic, then planning rendering order: starfield background, alien sprites, bunker cells shaded by row, shots, player cannon sprite built from rects with invulnerability blink, ground line, HUD with score and lives icons, and game-over/win overlays with restart prompt, plus a screen shake effect on damage.

For input handling, I'm mapping arrow keys and WASD to movement, space to fire with preventDefault to stop scrolling, and R to restart; I'm also making sure the restart button doesn't accidentally trigger from spacebar by setting tabIndex=-1. I'm setting canvas dataset attributes for status, score, lives, and alien/bunker counts for accessibility, then writing the main game loop using requestAnimationFrame with delta-time clamping.

Now I'm drawing sprites from row-based pixel strings, sizing them at 32px, and rendering enemy bullets with a zigzag pattern and a bright core. I'm also writing the player draw function with a blinking invulnerability effect and defining its collision rectangle bounds.

For bunkers, I'm coloring cells by row and filling 5x5 blocks solid, adding explosion particles when they're hit, plus a score popup helper and game-over/win overlay text. I still need to handle alien shooter selection, bunker shielding during enemy fire, and make sure particle effects keep updating after the game ends, along with a final boundary check in the update loop.

I'm double-checking the shot sweep logic for both player and enemy bullets to make sure collision detection covers the full travel distance, and confirming edge cases like game-over state transitions and keyboard input handling don't break anything.

The screenshot renders fine and that console warning is just from the sandbox iframe, not my code. Now I want to test movement and firing using the key action in the browser tool, though I'm not sure it'll expose my custom data attributes for inspection.

Checking the bunker collision logic against player and alien shot sweeps, and verifying the game-over threshold against where bunkers and aliens sit vertically -- those all look consistent. Let me run a quick movement test now.

I notice the lives counter dropped from 3 ships to 2 between the first screenshot and the later ones, suggesting the player got hit by an enemy shot despite the bunkers also showing damage.

I suspect a real bug here: tapping Space fires a keydown then keyup so fast the game loop might miss it since fire state resets before update sees it, same for movement taps. The fix is to latch key presses with a pending flag set on keydown that gets consumed during update rather than relying on the instantaneous held state. I still can't directly inspect game state since the browser tool only gives me DOM, not arbitrary JS eval, so I need to reason about the lost life purely from screenshot evidence rather than confirm it programmatically.

My previous edits had malformed arguments, so I need to redo this properly as a single correct edit: adding a fireQueued flag alongside the keys object, then updating the fire condition to check both keys.fire and fireQueued, resetting the queue after firing.

The shot now fires and is visible, and the formation is moving as expected. I've gathered enough evidence already, though I could quickly test the restart key as one more sanity check before wrapping up.