POKéMON SL0P EDITION
A cheeky romhack of Pokémon Yellow, built on the pret/pokeyellow disassembly. Everything is done in pure GBZ80 assembly and used entirely in-game — no external cheat device, no Game Genie. Press SELECT in the overworld and go wild.
Author: Ash Ketchum · runs on real hardware / any accurate GBC emulator.
✨ Highlights
- ⚡ Fastboot — got a save? Skip the intro, title, and CONTINUE menu and drop straight into the overworld.
- 🎬 Custom boot splash — a real 2bpp POKéMON · SL0P · EDITION graphic.
- 🎛️ The SL0P MENU (SELECT) — a table-driven cheat menu: instant heal, money, coins, badges, full dex, a maxed team, movesets, HMs, ×99 items, a no-wild-encounters toggle, and a fly-warp to any town.
- 🗺️ EXPLORE — a free-flying overworld camera that smooth-scrolls across the whole seamless Kanto map, gliding over map connections, and can warp you to wherever you're looking.
- 💤 SAVER — a screensaver that puts EXPLORE on autopilot and drifts the camera across Kanto on its own.
📸 Screenshots
the SL0P menu → SAVER screensaver, captured from a deterministic input replay
| The SL0P menu | Fly-warp submenu |
|---|---|
 |
 |
| EXPLORE camera (▲▼◀▶ = where you can go) | SAVER screensaver drifting over Celadon |
|---|---|
 |
 |
🎛️ The SL0P MENU
Press SELECT in the overworld. Move the cursor, A to pick, B to back out / close.
| Entry | Effect |
|---|---|
| WARP | fly-warp to any of 13 destinations (all towns + Route 4/10) |
| HEAL | full HP + clear status for the whole party |
| MONEY | ¥999,999 |
| COINS | 9,999 game-corner coins |
| BADGES | all 8 gym badges |
| DEX | mark every Pokémon owned + seen |
| MAXTEAM | whole party → Lv100, perfect DVs, maxed EVs, 999 stats/HP |
| TEACH | give everyone Hyper Beam / Earthquake / Ice Beam / Thunderbolt |
| HMS | give all five HMs (Cut/Fly/Surf/Strength/Flash) |
| ITEMS | ×99 of balls, Rare Candy, Full Restore, Max Revive, Max Elixer, PP Up + all five evolution stones |
| NOWILD | toggle wild encounters off |
| REPEL | refill repel steps |
| EXPLORE | free-flying overworld camera (see below) |
| SAVER | overworld screensaver (see below) |
🗺️ EXPLORE
A self-contained camera that flies over the seamless Kanto overworld with a real hardware smooth-scroll — no character walking. The d-pad pans a screen at a time and glides straight across map connections at the edges; ▲▼◀▶ arrows show which ways you can go. Press A to warp your trainer onto the tile you're looking at, or B to return to the menu.
💤 SAVER
EXPLORE on autopilot: it keeps drifting in one direction until it hits a bound, then turns and carries on, wandering across all of Kanto by itself. The arrows and your trainer/Pikachu are hidden for a clean view. Press any button to wake it.
🛠️ Build & play
Needs RGBDS v1.0.1 on your PATH
(rgbasm / rgblink / rgbfix / rgbgfx). See INSTALL.md for
toolchain setup.
make # -> pokeyellow.gbc (ship this one)
Load pokeyellow.gbc in any accurate Game Boy Color emulator (or flash it to a
cart) and press SELECT in the overworld. The build is reproducible; the boot
splash regenerates from gfx/slop/intro.png.
🧩 How it's built
Almost everything lives in a handful of files, chiefly engine/slop_menu.asm
(the SELECT menu + the EXPLORE/SAVER camera). Adding a menu entry is three lines.
The overworld camera reuses the walking engine's own smooth-scroll machinery
(hSCX/hSCY, the rotating VRAM map pointer, and the vblank row/column redraws) to
scroll pixel-by-pixel and stream map connections.
For the full technical write-up — the menu/handler dispatch, the smooth-scroll and map-crossing math, the screensaver's wander logic, and the WRAM/ROM budget notes — see SL0P.md.
🙏 Credits
- Built on the pret/pokeyellow disassembly — see README.pret.md for the upstream project, and huge thanks to the pret team and contributors.
- Pokémon is © Nintendo / Game Freak / The Pokémon Company. This is a non-commercial fan project; no ROM is distributed — bring your own and build from source.