Open the Editor

Browser game maker · real NES output

Make a game.
Get a cartridge.

Draw a cave. Talk to a cat. Flash it to a cartridge. NESty compiles your game straight to 6502 and hands you a .nes that boots on real hardware — no assembly required, none of it faked in an emulator wrapper.

Open the Editor → See how it builds

Runs in the browser. Free. Draw → 6502 → assemble → .nes.

It's a real cartridge. Not a save file.

Same spirit as Bitsy: walk around, talk to people, pick up things, be somewhere. No physics, no timers to fight — instant grid movement, one screen per room. The difference is what comes out the other end. NESty writes a hand-tuned 6502 engine, appends your game as data tables, and assembles the whole thing into an authentic NROM ROM. Play it in the built-in emulator, download the .nes, or burn it to an EverDrive and boot it on a front-loader from 1985.

Rooms & tiles

Paint a 16×15 grid of 16×16 tiles — exactly one NES screen. Wall flags for collision, 2-frame tile animation, exits that teleport between rooms.

Sprites & avatar

16×16 metasprites built from four hardware sprites. Directional avatar art, a walk-cycle flip, NPCs and pickups you place per room.

Dialog

A paged text box, 28 columns by two lines, with a typewriter crawl you can set from instant to turbo — and a per-character blip if you want one.

Logic that holds up

Flags and variables, conditions, room events that fire when you step on a cell, tile overlays that swap art when a door opens. No scripting language to learn — you wire it in the editor.

Sound on the real APU

A Nanoloop-style tracker: 16-step patterns across four channels — pulse 1, pulse 2, triangle, noise. Plus up to 32 custom sound effects you trigger from events. It plays through the chip, not a sample.

Transitions & polish

Screen wipes between rooms — scroll, diagonal, fade, curtain, blinds. Five fonts including katakana. Optional splash screen at boot.

Look inside

One window, no panels to hunt for. Paint a room, wire the logic, punch in a song on the step grid, write the dialog — the ROM rebuilds as you go.

The NESty world editor: a room of tiles with a cat sprite, the tools rail, room tree and entity inspector
World editor — paint the room, place NPCs, exits and endings.
The NESty music tracker with a 16-step note grid across four channels
Music — a 16-step tracker across four APU channels.
The NESty dialogue editor showing a text box preview and the list of all dialogs
Dialogue — write it, see the NES text box render live.

Try it yourself →

Play one right now

This is a real .nes ROM built with NESty, running on the jsnes emulator in your browser — the same ROM you'd flash to a cartridge. Arrows walk, Z talks, Enter starts.

Click the screen to grab the controls.

What happens when you hit Play

No native toolchain, no download, no account. The whole compiler runs in the tab you already have open.

  1. 1

    Draw

    Rooms, tiles, sprites, dialog, palettes, songs — in the editor.

  2. 2

    Compile to 6502

    Your game becomes commented assembly against the NESty engine.

  3. 3

    Assemble

    A two-pass 6502 assembler builds an iNES ROM, right in the browser.

  4. 4

    Play it

    Boots on the embedded emulator. Download the .nes. Flash it.

The .asm you download is the complete engine plus your game as readable data tables. Assemble it again with the bundled assembler or with ca65 — it's yours to study and hack.

The fine print, because it matters

NESty models the real machine, not a loose approximation. When something won't fit on hardware, the editor tells you before you flash it.

Cartridge
Mapper0 — NROM, horizontal mirroring
PRG ROM32 KB
CHR ROM8 KB — 256 BG + 256 sprite tiles
OutputiNES .nes + .asm + .chr
Runs onMesen · FCEUX · EverDrive · jsnes
Picture
Resolution256 × 240, one screen per room
Room grid16 × 15 cells of 16 × 16 px
PaletteFull 64-color 2C02 master ($0D blocked)
Sub-palettes4 BG + 4 sprite, one BG palette per cell
CHRAutomatic 8×8 tile dedup
Budgets (enforced live)
Rooms≤ 24
Tiles≤ 160
Sprites + items / room≤ 15
Flags · Vars≤ 16 · ≤ 8
Events · Custom SFX≤ 128 · ≤ 32

Line up four sprites on one row and the editor warns you — that's the NES eight-per-scanline limit talking, and it'll flicker on real silicon. Overrun 32 KB and the build stops. The constraints are the craft.

A game is a text file

Everything you draw round-trips to a line-oriented format on the data tab. Readable, diffable, paste-able. Here's the top of a small one: 

GAME my cave adventure
VER 1
START 0 7,7

PAL 0
BKG 0F
BG0 21,11,30
SP0 30,27,16

TIL a
NAME rock
WALL true
<16 rows of 16 pixels, 0-3>

ROOM 0
PAL 0
<15 rows of 16 tile ids>
EXT 15,7 1 0,7      ; exit -> room 1
END e 8,3          ; ending dialog e
ITM k 3,9          ; item placement

DLG c
Meow. The cave is deeper than it looks.

Enough reading. Draw something.

Open the editor and load the sample game — you'll have a ROM in a minute.

Open the Editor →