Space Invaders · gemini-3.5-flash-lite

**Initiating Project: Space Invaders**

I'm starting a new project – a Space Invaders game in `index.html`. My focus is on robust design and a polished feel, and I'm planning canvas-based rendering for a crisp retro aesthetic. I'll be drawing pixel art using Canvas 2D primitives. The player cannon controls will use Left/Right or A/D.


**Defining Game Mechanics**

I've been solidifying the game's core mechanics. Spacebar will be the fire control, with a cooldown and projectile lifetime. The alien grid is taking shape: multiple rows, horizontal movement, and a speed increase as they thin out, firing downward. Bunkers will be destructible, with each hit chipping away at them. I'm also planning the lives system and game over conditions (aliens reaching the player or lives running out) plus a restart.


**Architecting The HTML**

I'm now deep in the HTML architecture phase. The plan is a container with a retro arcade cabinet feel, or possibly a clean, modern layout. I'm building a header/HUD for score, lives, high score, and status. The canvas element will be the game's core, possibly 800x600, scaled with CSS. Controls and the restart button will go below the canvas.


**Implementing Game Loop & Graphics**

I'm now fully immersed in implementing the game loop and graphics rendering. My focus is on robust collision detection with alien movement updates. Procedural drawing functions for the player cannon, diverse alien types (squid, crab, octopus, etc.), bunkers, bullets, and explosions are underway. For the destructible bunkers, I'm leaning toward an offscreen canvas per bunker. It will allow super-fast and accurate destruction rendering with `destination-out`. The game loop will use `requestAnimationFrame` for smooth updates, handling all player actions, bullet updates, and alien movement.


**Finalizing Gameplay Logic**

I'm now deep in implementing the final gameplay logic. I've defined alien behavior: horizontal movement with reversals and descent at edges, coupled with increasing speed. I've also implemented random firing logic for the bottom-most aliens. Collision detection is now complete for bullets, aliens, and the player, including bunker destruction and scoring. The final `index.html` file and test are underway. I'm double-checking the bunker implementation, especially with the offscreen canvas.


**Refining Bunker Destruction**

I've been refining the bunker destruction mechanics using an offscreen canvas. I'm focusing on precisely modeling the bunker's damage using `destination-out`. This includes cutting out the classic bunker shape (arch at the bottom and top corners) to achieve a visually accurate destruction effect. I'm also planning the `damage()` method to implement damage based on an incoming projectile's position (bx, by) to the bunker's top-left corner (x,y) with a radius.


**Optimizing Bunker Collision**

I'm now optimizing the bunker collision detection. I'm focusing on the `checkCollision()` method, making sure that there is an alpha check using `getImageData` only if the initial bounding box check succeeds. The logic involves checking pixel alpha in the offscreen canvas to optimize pixel-perfect damage. I'm confident in a performance boost.


**Defining Game Entities**

I'm now deep in defining game entities such as the canvas size, player cannon dimensions, and the alien grid's structure with scoring. I'm solidifying the player's firing mechanics, including the cooldown and projectile limitations. I've also detailed the aliens' behavior, including edge detection, direction reversals, and speed increases based on the remaining population.