Modbox

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.

Recreate “Modbox” as a first-person browser 3D sandbox in Three.js with a clean developer-toy aesthetic. The player is an unseen first-person capsule-style controller with mouse-look, a small pale crosshair/plus at the exact screen center, and pointer-lock controls. Start in a dark navy/black test arena at position approximately (0, 2.2, 8), with a large flat dark-blue ground plane, subtle blue grid lines, blue-tinted ambient lighting, directional shadows, and fog fading into a deep navy background. Build a small obstacle playground from simple shadow-casting rectangular blocks: a broad low platform around the rear-center, a taller 6x5x6 block to the right, a tall tower on the left, a long low platform behind/forward, and another low block farther right. Use simple saturated materials and readable geometric forms rather than detailed textures.

Core loop: explore the test map, collect floating gold bolt pickups, then spend the currency in the Mod Terminal to install gameplay-changing mods. There is no win state; the sandbox goal is to unlock and experiment with all five mods. Persist bolts, installed mods, and pickup statistics in localStorage so progress survives reloads. The HUD is minimal and fixed over the game: a thin dark translucent outlined panel in the upper-left showing “Bolts” and the current number plus “Mods” and a comma-separated installed-mod summary (initially Bolts 0 and Mods (none)); a matching upper-right hint panel reading “Click to play • E = Mod Terminal”; and a wide bottom hint panel reading “WASD move • Space jump • Shift sprint • LMB use tool • RMB grapple (if bought) • R reset”. Show temporary centered/lower toast notifications for pickup, purchase, error, reset, grapple, and explosion feedback.

Place eight initial floating bolt pickups around the map, each as a glowing metallic gold torus/ring that rotates and bobs vertically. Locations should correspond to the platforms and open arena: roughly (0,1.6,-12), (12,6.2,-2), (-14,10.2,6), (-2,2,16), (20,3,18), (6,1.8,4), (-8,1.8,-2), and (16,1.8,-14). Each collected ring gives 5 bolts, plays a short synth pickup beep, disappears, and when fewer than six remain a replacement appears at a random location in a broad area and elevated random height. Use simple synth beeps/noise for pickup, buying, errors, jumping, tools, grapple, reset, and explosions.

Movement must feel like a lightweight FPS controller: WASD movement relative to camera heading, mouse look, normal speed 6, Shift sprint speed 9, acceleration/friction and air control, gravity, jumping with Space, collision against the ground and static boxes, and R reset to the starting position. Space is edge-triggered so one press jumps once. Esc unlocks the pointer; clicking the canvas starts/locks the mouse. E opens and closes the Mod Terminal, exits pointer lock when opened, and movement/input pauses while the terminal is open. Prevent the context menu for right-click.

The Mod Terminal is a dark readable overlay/modal opened with E. List each mod with name, description, cost in bolts, and a Buy button; after installation show an “Installed” tag and a “Re-install (noop)” button. The five purchasable mods and exact behavior are:
- Double Jump, cost 20: permits one additional mid-air jump per airborne cycle, with a distinct jump/toast cue.
- Low Gravity, cost 30: changes player gravity to a floatier value, lowers jump velocity slightly, and reduces maximum fall speed; it also makes spawned dynamic objects fall more slowly.
- Grapple Hook, cost 40: while pointer locked, RMB raycasts from the center crosshair up to about 90 units at static boxes or dynamic objects, attaches to the hit point if found, and displays a success/error toast. Holding RMB reels the rope in, applying pull when beyond the rope length; releasing RMB detaches. Include a short cooldown and a grapple sound.
- Toolgun: Prop Spawner, cost 35: changes LMB behavior so a center-screen raycast hit spawns a physics prop just off the hit surface. Props are simple one-unit colored cubes with random hues, shadows, slight initial velocity, gravity, bouncing, and damping; they can be stacked or used as sandbox objects. Without this mod, LMB instead acts as a basic tool/gun that raycasts, gives a sound, and applies an impulse to a hit dynamic object (or simply pings static geometry/no hit).
- Boom Barrels, cost 25: once bought, add four red cylindrical barrels to the map at approximately (6,3,-8), (-8,3,-10), (18,3,8), and (-18,3,18). They are dynamic physics objects. The basic LMB tool can shoot a barrel; one hit destroys it, creating a brief orange point-light flash, explosion sound/toast “BOOM.”, and radial impulse on nearby dynamic objects plus a shove/upward impulse to the player if close.

Use raycasting from the camera center for tools. Dynamic cubes and barrels should fall under gravity, bounce on the ground, and be lightly damped. Static boxes should cast/receive shadows and act as player colliders. Keep the overall presentation sparse, dark, blue-violet, and highly legible, with gold pickups, cyan/random-color props, and red barrels providing strong color accents. Begin with the non-modal toast “Click to play. Collect bolts. Press E to buy mods.” and update HUD values immediately after pickups or purchases.