Issues

• Black Inset Border of Canvas Obstructing Display of Pixels

  bfirsh/jsnes#826 · Filter by author JoeMeeks opened on Sep 13, 2026
  1

• Mapper 2 Game Graphics Corruption

  bfirsh/jsnes#820 · Filter by author liminmsn opened on Sep 5, 2026
  1

• Super Mario Bros. 3 and Kirby's Adventure sprite layer error and Audio issue

  bfirsh/jsnes#771 · Filter by author JeraldDude opened on Jul 12, 2026

• Tetris (NES) compatibility issues? (disappearing graphics)

  bfirsh/jsnes#751 · Filter by author cIymax opened on Jun 20, 2026

• MMC1 (mapper 1): SUROM 512KB games crash — fixed bank at $C000 doesn’t follow the 256KB page-select bit

  bfirsh/jsnes#732 · Filter by author Azsoft-jp opened on Jun 3, 2026

• Fix sprite corruption in Castlevania III intro

  bfirsh/jsnes#647 · Filter by author bfirsh opened on Mar 7, 2026
  2

• Test coverage gaps: PPU, APU, controllers, mappers, browser, state serialization

  difficulty: hardenhancementpriority: medium
  bfirsh/jsnes#617 · Filter by author bfirsh opened on Feb 28, 2026

• TypeScript type definitions are incorrect

  bugcomponent: browserdifficulty: easypriority: medium
  bfirsh/jsnes#610 · Filter by author bfirsh opened on Feb 28, 2026

• APU: various channel bugs (sequencer reset, length counter gating, timer stepping, noise LFSR)

  accuracybugcomponent: apudifficulty: mediumpriority: medium
  bfirsh/jsnes#609 · Filter by author bfirsh opened on Feb 28, 2026

• PPU: minor rendering issues (odd-frame skip, monochrome bg, sprite 0 left-column)

  accuracybugcomponent: ppudifficulty: easypriority: low
  bfirsh/jsnes#607 · Filter by author bfirsh opened on Feb 28, 2026

• PPU: no 8-sprite-per-scanline limit or sprite overflow flag

  accuracybugcomponent: ppudifficulty: mediumpriority: high
  bfirsh/jsnes#604 · Filter by author bfirsh opened on Feb 28, 2026

• CPU: CLI/SEI/PLP interrupt inhibit delay and BRK/NMI hijacking not implemented

  accuracycomponent: cpudifficulty: hardenhancementpriority: low
  bfirsh/jsnes#603 · Filter by author bfirsh opened on Feb 28, 2026

• CPU: IRQ and reset interrupt handlers missing proper cycle timing

  accuracybugcomponent: cpudifficulty: mediumpriority: medium
  bfirsh/jsnes#602 · Filter by author bfirsh opened on Feb 28, 2026

• Most mappers missing toJSON/fromJSON — save states lose bank state

  bugcomponent: mapperdifficulty: mediumpriority: medium
  bfirsh/jsnes#600 · Filter by author bfirsh opened on Feb 28, 2026

• Add missing popular mappers (206, VRC, FME-7, MMC4)

  component: mapperdifficulty: hardenhancementpriority: medium
  bfirsh/jsnes#599 · Filter by author bfirsh opened on Feb 28, 2026

• MMC1: multiple shift register and mirroring bugs

  accuracybugcomponent: mapperdifficulty: mediumpriority: medium
  bfirsh/jsnes#598 · Filter by author bfirsh opened on Feb 28, 2026

• MMC5 (Mapper 5): completely non-functional stub

  bugcomponent: mapperdifficulty: hardpriority: high
  bfirsh/jsnes#596 · Filter by author bfirsh opened on Feb 28, 2026

• MMC3: IRQ counter has multiple correctness issues

  accuracybugcomponent: mapperdifficulty: hardpriority: critical
  bfirsh/jsnes#595 · Filter by author bfirsh opened on Feb 28, 2026

• ROM loader: header zeroing heuristic breaks NES 2.0 ROMs

  bugcomponent: romdifficulty: mediumpriority: high
  bfirsh/jsnes#593 · Filter by author bfirsh opened on Feb 28, 2026

• AccuracyCoin: 32 remaining test failures

  bfirsh/jsnes#591 · Filter by author bfirsh opened on Feb 28, 2026

• Mapper coverage: status and roadmap

  bfirsh/jsnes#568 · Filter by author bfirsh opened on Feb 16, 2026

• Implement dot-level PPU rendering pipeline

  bfirsh/jsnes#565 · Filter by author bfirsh opened on Feb 15, 2026

• Phone/tablet/touchscreen interface

  bfirsh/jsnes#564 · Filter by author bfirsh opened on Feb 15, 2026

• Sprite issues in Punch-Out

  bfirsh/jsnes#561 · Filter by author bfirsh opened on Feb 15, 2026

• Implement cycle-accurate DMA bus interleaving

  bfirsh/jsnes#535 · Filter by author bfirsh opened on Feb 12, 2026
  1