Gem Run

Cinevva's analyzer read this game's design doc and its source, then wrote the brief below. "Make your own" hands it to the game creator as your opening message, so you start from a real spec rather than a one-line idea.

Create a browser-playable 2D retro pixel-art side-scrolling platformer titled "Gem Run". Use a crisp, nearest-neighbor/pixelated 320x180 virtual canvas that scales to fill the browser, with a fixed side-view camera following the player horizontally through compact tile-based stages. The visual style is bright 16-bit-inspired platformer art using Kenney-style pixel sprites: a small yellow-clad player character, gold coin, blue key-shaped gem, red flag, purple floating platforms, grassy block ground, walking slime and snail enemies, and a wooden sign by the starting point. The background is a cheerful blue sky with pale cloud layers and a faded blue tree/hill silhouette; clouds and trees scroll at slower parallax rates than the foreground. Keep a dark purple strip along the bottom of the viewport as part of the game presentation.

Build exactly two short levels, each represented as a 64-column by 16-row tile layout. The player begins near the left on solid grassy ground, with gaps/pits between separated ground sections, elevated purple platforms for jump routes, coins and blue gems suspended above the route, patrolling enemies, and a flag near the far right. Level 1 is a warm-up with multiple coins, one gem, several pits, two enemies, and a final flag. Level 2 has tighter spacing, elevated platforms, more patrol pressure, coins, two blue gems as placed in the level data, and the final flag. Ground blocks form the bottom rows wherever the map has ground; empty columns create lethal pits, visually represented with lava tiles below the playable floor. Do not add procedural features, weapons, checkpoints, or additional stages.

Controls: ArrowLeft and ArrowRight move horizontally; Z or Space jumps. Horizontal movement is direct and responsive at about 102 pixels/second. Jump with roughly 270 pixels/second upward velocity, gravity around 820, and a maximum fall speed around 360. Support a short jump input buffer (about 0.14 seconds) so a jump pressed just before landing triggers on landing. Provide on-screen mobile controls on small screens: large left and right buttons grouped at bottom-left and a large JUMP button at bottom-right; hide these buttons on wide desktop screens. Prevent page scrolling while playing.

Implement solid collision against ground and purple platforms, including horizontal and vertical resolution. The player can collect coins and gems by touching them; collectibles gently bob vertically. Coins award 100 points and gems award 250 points, disappear when collected, play a light pickup sound, and update the message. Enemies patrol automatically at about 26 pixels/second, turn around at walls or when there is no floor ahead, fall under gravity, and alternate between slime and snail sprites. Touching an enemy removes one of the player's three hearts, knocks the player back/upward, plays a hurt sound, and grants about 1.1 seconds of blinking invulnerability. If all hearts are lost, show game over. Falling below the level is an immediate game over regardless of remaining hearts.

The player must overlap the red flag at the right edge to clear a level. Play a win sound and briefly show "Stage clear! Next level..." before automatically loading the next level while retaining the score and remaining hearts. Clearing the second level enters a victory state and displays the final score. In game-over or victory states, show an instruction to press R, Enter, or Space to restart; restart resets to level 1 with score 0 and 3 hearts. Include a brief loading state while assets load.

Add a chunky overlay HUD in the browser UI, separate from the canvas: a translucent dark-purple panel at the upper-left with up to three pixel heart icons, "SCORE 0000" using zero-padded score, and "LEVEL 1/2" or "LEVEL 2/2". Center a prominent message panel near the top with a yellow border for prompts such as the level intro, collectible feedback, damage, stage clear, game over, and victory. At the lower-left show a smaller hint panel describing the controls and pit/enemy rules. Use a Pixelify Sans-like chunky pixel font, dark purple translucent panels, pale text, cyan borders, and yellow accent borders. Include simple retro sound effects for jumping, collecting, damage, winning, and losing, but gameplay must remain understandable without sound.