- Added Stage 6: Laboratory - Added the new Stage 6 boss, Prototype-X - Prototype-X brings new attacks: corrosive claw, poison spray, jump slam, and a deadly red death ray - Added the Stage 6 clear achievement - Fixed the ending / credits timing so it appears after Stage 6 - Fixed Stage Select clear status display for the final stage - Shop upgrade prices now scale with the player's current upgrade level - Added various balance, UI, and release workflow improvements

- Fixed iOS shop touch handling: the Helicopter Shop now explicitly supports screen-touch input for item cards, upgrades, and the Next Stage button - Enlarged the shop Next Stage touch target to improve reliability on iPhone - Moved the shop Gold / HP status panel under the shop subtitle so current resources are visible before buying upgrades - Adjusted Helicopter Shop spacing so the resource panel, item cards, and Next Stage button have clearer separation - Added documentation for the iOS shop Next Stage touch issue, suspected cause, fix, and regression test steps

- Added Simplified Chinese support

- Improved Flame Dash visual effects (removed generic circle outline, added custom flame aura) and added screen shake/controller vibration feedback - Improved Boss 1 ultimate skill visual effects (removed generic circle outline, added Boss burning aura) - Updated Game Over screen stats to display stage-specific highest score and longest survival time instead of global records, and removed the "LV" display - Improved the appearance of the Surrender button on the Game Over screen to match other buttons when not focused - Fixed a critical bug in Boss Rush mode where selecting "Restart" would incorrectly return the player to Campaign Stage 1 - Fixed a bug in Boss Rush mode where the Stage Select screen would not respond to inputs after completing the mode - Fixed a bug where pressing the Cancel button (B) on the controller in the Game Over screen could trigger unintended actions instead of Surrender

- Added Stage Select screen with Taipei map background and 5 playable stages, each with unique theme, arena, and boss - Added stage unlock progression — completing a stage unlocks the next one - Added Boss Rush mode accessible from Stage Select - Added in-game Surrender button on pause and game-over screens to return to Stage Select - Added permanent upgrade persistence — shop upgrades carry over across stage clears - Fixed restart after game over now returns to the selected campaign stage instead of restarting from stage 1 - Fixed controller focus and navigation on game-over screen

- Added mission briefing screen before each boss wave with animated intro - Added shop upgrade icons for spray range, damage, and efficiency - Added shop continue delay (0.8s arm time) to prevent accidental skip - Fixed shop touch/mouse click not updating focus — tapping an item now moves focus to it even when purchase fails

- Added earthquake special attack for Boss 5 (Kurogane Shogun) with screen shake and area damage - Added needle dash special attack for Needle Rat enemy - Added poison cloud on death for Poison Rat enemy - Added rage mode on low health for Rage Rat enemy - Added death explosion for Bomb Rat enemy - Added all 5 boss ultimate skills with full VFX and SFX - Added new sound effects: explosion, needle dash, poison cloud, earthquake - Added new visual effect textures: poison burst cloud, fireball, laser beam - Added boss topdown sprites for all tiers - Fixed poison cloud visual size to match actual damage radius - Fixed earthquake boss not triggering correctly (was falling through to charge logic)