v0.9.21

Amy now uses her original artwork for 1-UP monitor faces, rising reward sprites and continue-award icons. The sprite palette follows dry and underwater colors without adding a background composition pass.

The bounded Nemesis decoder also handles a final run that extends past the declared output row, matching native termination while keeping output bounded.

QA credit: TheGabeMaster29.

Sonic the Hedgehog 2 v0.9.20

Correct native foreground sprite ordering, Knuckles wall-push poses and glide contact/recovery. Restore save selection when rewinding back to the menu, preserve controller input through character adapters, extend original water-surface artwork across wider views and center custom-character act-clear headings.

Fresh launcher settings use Fit to screen; saved aspect, mod and input choices are preserved.

QA credit: TheGabeMaster29.

Sonic 2 v0.9.19

Knuckles' signpost spin now uses the original lock-on colours throughout its native frames, including Tails' face and the blurred views. The original artwork, pole, geometry and spin sequence are preserved.

Fresh launcher settings use Fit to screen; existing saved aspect, mod and input choices are preserved. Existing imported and companion special-stage support limits remain.

QA credit: TheGabeMaster29.

Sonic 2 v0.9.18

Competition mode keeps its screen divider in place through demo exit fades and manual skips.

Knuckles' half-pipe HUD follows the original Knuckles-in-Sonic-2 layout and checkpoint colours. HUD rendering avoids a redundant scan of Amy's name sprites. Special-stage results clear pending world tile redraws before drawing the result screen, and cold-state restoration clears native dispatch bookkeeping before execution resumes.

Fresh launcher settings use Fit to screen. Existing saved aspect, mod and input choices are preserved. Other imported and companion special-stage roles retain their existing support limits.

QA credit: TheGabeMaster29.

Sonic the Hedgehog 2 v0.9.16

Amy now uses her original half-pipe animation, palette and primary HUD artwork. Solo Amy uses the native one-player role; Amy with Tails retains the native two-player roles. Solo result screens use matching original artwork, and native emerald awards and level returns retain their behavior.

Special-stage palette overrides apply to sprites while native planes retain their ordinary rendering path. Existing world and Shadow palette providers retain their behavior.

Other imported and companion special-stage roles retain their current support limits.

QA credit: TheGabeMaster29.

v0.9.15

Knuckles now uses the original half-pipe sprite artwork, palette and solo result layouts. Sonic, Tails and Knuckles solo rosters select their native special-stage controller.

Validated native and widescreen rendering, emerald awards and return to gameplay, current-build save/load, rewind, replay, rollback, packaged launcher settings and runtime parity.

QA credit: TheGabeMaster29.

Sonic the Hedgehog 2 v0.9.14

Fixes valid long pauses being mistaken for runaway native execution, while retaining protection against loops that make no progress.

Validated current-build saves, replay, rollback and matching gameplay/audio state across native, co-op and split-screen workloads. Runtime measurements are neutral/inconclusive within variation; this release makes no speedup claim.

Sonic the Hedgehog 2 v0.9.13

Restore Knuckles' original collision-box transitions, wall/climb probes, terrain recovery and boss rebound. Custom characters now follow native palette-fade timing and scanline water boundaries. Act-clear screens use the selected character's name, and Knuckles uses his original monitor and continue-award artwork. Native HUD and title-card lettering correctly covers character overlays, including character-specific competition HUDs.

Special stages use native Sonic/Tails roles. Existing in-game saves and settings are preserved; save states remain specific to the build.

QA: @TheGabeMaster29.

Sonic the Hedgehog 2 v0.9.12

Correct native Emerald Hill scrolling for custom and mixed character parties.

The last two scroll rows now use the original Knuckles-in-Sonic-2 correction whenever the validated roster differs from solo Sonic, solo Tails or the canonical Sonic+Tails duo. This includes reversed pairs, custom characters and active extra companions. Unused seats preserve original classic-roster fidelity. Existing Knuckles-leading behavior, widescreen output and native VS scrolling are preserved.

The runtime engine and launcher code are unchanged; the engine pin includes a documentation refresh. Fresh installs retain adaptive widescreen Fit to screen; explicit saved choices and native in-game saves remain intact. Quicksaves are specific to the exact build. Supply your own supported ROM and optional donor images; no ROM data ships.

The existing very-long-pause watchdog defect remains tracked separately and is not claimed fixed here. Broader platform/layout/collision/rewind enhancements are outside this release.

Validation passed: 25 focused tests, 17 matched roster cases with 51 paired snapshots, 23 quickstate fixtures, 2,000 matched replay executions, 117 rollback checks, and special-stage warm/cold restoration and track-map checks. The exact archive passed its dependency/allowlist checks and shipped replay helper; launcher persistence and fresh/saved aspect choices were checked with actual gameplay output. Two-roster CPU-time comparisons were neutral/inconclusive within the observed variation.

Sonic the Hedgehog 2 v0.9.11

Corrects behavior across Knuckles presentation, save menus, widescreen backgrounds and special-stage saves.

• Restore original Knuckles title/HUD/monitor artwork and hurt, death, ledge and glide-landing behavior, including EHZ2 boss-floor landing.
• Keep donor characters behind results text and countdown digits while preserving normal priority terrain.
• Correct save-menu start feedback, departure presentation and character/counter details.
• Correct the qualified attract-fade, left-edge background and title-card presentation cases.
• Preserve ordinary gameplay and menu proportions through native special-stage entry and return. Special-stage saves wait for a complete track, including fresh-process reloads.
• Accept Steam .68k ROM images and retain the established launcher settings behavior.

Fresh installs continue to enable adaptive widescreen Fit to screen; existing explicit choices and native in-game saves are preserved. Quicksaves are specific to the exact build. Supply your own supported Sonic 2 ROM and any optional donor images; no ROM data is included.

Original special-stage percussion and the white fade remain unchanged. Larger parties and donor actors retain original-rate motion under high refresh mode.

Validation includes focused correctness tests, current-build save/load, replay and rollback, source-pixel and recorded-route checks, representative shared-engine consumer checks and packaged dependency/defaults checks. Validation remains bounded to the tested configurations.

An existing framework watchdog can eventually abort a very long native pause. The same failure was reproduced in v0.9.10; it is tracked separately and is not claimed fixed here.