Build your own original browser arena prototype, inspired by COUNTERFORGE, an original Vibe1Up game. Choose a new name for your build. The hook: enemies bring the ammunition; you catch it and fire it back. Deliver a complete, playable single self-contained index.html using 2D Canvas, CSS and plain JavaScript, with no libraries, runtime CDN, backend, login or paid assets. This is a simplified learning prototype, not a recreation of the featured 3D game's art.

CORE LOOP
- Fit the arena and controls in one phone viewport without page scrolling. Use a dark steel floor, a cyan mech, amber capturable rounds, red heavy rounds and bright mint returned shots. Use simple original shapes, readable silhouettes and clear wind-up cues.
- Move with WASD/arrows or a left-thumb joystick. Hold Space or the right-thumb button to raise a circular magnetic field. Capture amber rounds that actually enter that field: remove each hostile round and store it in a visible bank, capped at 10.
- Release to launch the bank as real projectiles toward the nearest living enemy. Deal damage only when a returned projectile makes a collision; never award damage or points just for pressing the button. Empty release does nothing.
- Start with 6 armor. Red heavy rounds bypass the field; dodge them. Show a short damage-invulnerability window so one hit is not counted every frame.
- Heat rises while holding and with each capture. At 100%, dump the bank, visibly overload, and disable capture for 2 seconds. Releasing early cools the field. Display bank, armor and heat without covering the action.

ONE FINISHABLE ENCOUNTER
Start with three stationary sentries that telegraph aimed amber volleys; stagger their attacks. After they fall, spawn a collectible core. Touching it attaches a visible second barrel and doubles the returned projectiles. Then spawn one captain with two destructible gun pods. Defeat the pods before the core. Red heavy shots are clearly telegraphed and never capturable. Show victory or defeat, score, biggest bank, and a replay button. Do not add currencies, shops, logins or extra levels.

CONTROL AND RELIABILITY RULES
Run simulation at a fixed 60 updates/second, independent of rendering speed. Track independent pointer IDs with pointer capture: lifting either thumb must not end the other thumb's action. A pointer cancel, lost focus, tab hide, pause or resize must clear held input WITHOUT firing a stored bank. Pause on tab hide and require an explicit Resume. Provide Start, Pause/Resume, Restart and optional sound toggle; audio starts only after user interaction. Save best score locally, but continue normally if storage is denied. Support reduced motion and keep touch targets at least 44 CSS pixels.

DELIVER AND CHECK
Return the entire working file, a short controls guide and a truthful list of checks actually run. Check real capture/removal, release/collision damage, empty release, overload, red-heavy damage, both finger-release orders, cancelled-touch no-fire, pause/resume, upgrade, boss progression, victory/defeat and replay. Start readable and fair. If something is not tested, say so. Make this core playable before adding visual polish.