For developers with an old game
Remake your game in Summer, from old code to a better version
An old game is the best spec you will ever have. You know how it should feel, what players liked and what never worked. Here is how to decide between a remake and a remaster, what to carry over, and how to rebuild it in an order that stays playable.
The short answer
To remake your game in Summer, first decide whether it is a remake, which rebuilds and modernizes the game, or a remaster, which stays faithful and mainly upgrades assets. Keep the design, the tuning values, the level layouts and every asset you own or license outside the old engine. Start from a Summer template near your genre, then rebuild in this order, the player controller, one level, the core loop, UI and content. Give the agent your old code and design notes as the spec for each system, and playtest in the engine after every step, comparing the numbers with the original.
Most developers have one. A jam game that deserved more, a first project in an engine you no longer use, or a finished game that aged badly. Remaking it is one of the best projects you can pick, because the hardest question in game development, what should this feel like, is already answered. The old build is playable proof.
It is also easy to get wrong. Remakes stall when the scope quietly grows into a sequel, when old code is copied line by line into a new engine, or when the new version never quite feels like the old one and nobody can say why. This guide gives a plan that avoids all three, with Summer doing the rebuilding and you doing the judging.
What it does
Start from a template
Summer templates give you a working project in your genre to build from. You replace and extend systems instead of wiring an empty project.
Old code as the spec
Summer's in-app agent reads the files you give it, such as C#, GML, JavaScript, Blueprint notes or a design doc, and rebuilds one system at a time in GDScript inside your project.
Assets carry over
Summer is compatible with Godot 4 and imports glTF 2.0 models, PNG and JPG textures, and WAV, Ogg Vorbis and MP3 audio, so the art and sound you own move straight in.
Playtesting you can measure
The agent can run the game, send scripted input with summer_game_input, and read frame-stamped state and a screenshot with summer_game_probe. A jump height or a dash distance becomes a number you compare with the original.
New assets where the old ones do not fit
Summer Studio generates 3D models, 2D art, sound effects, music and voices when the old assets are too low resolution, locked to another engine, or not yours to reuse.
Desktop builds for release
Summer builds Windows and macOS versions for Steam and itch.io downloads once the export templates are installed. Web export is not available in Summer yet.
How it works
- 1
Step 1: Decide remake or remaster
A remaster stays faithful and mostly upgrades assets and convenience. A remake rebuilds the game and may change how it plays, as the 2019 Resident Evil 2 replaced tank controls with an over-the-shoulder camera. Write one sentence on what changes and what must not, and keep it next to the project.
- 2
Step 2: Harvest the spec from the old game
Collect the design notes, record a few minutes of play, and extract every tuning value from the code, such as speeds, gravity, jump strength, timings, damage and spawn rates. Note the units and convert frames to seconds where needed.
- 3
Step 3: Sort the assets by ownership
Mark each model, texture, sound and track as yours, licensed for use outside the old engine, or not reusable. Some marketplace assets are locked to one engine, such as Megascans used through Quixel Bridge, which Epic treats as UE-Only Content, and others carry their own terms, so read each license before you import it.
- 4
Step 4: Start from a template and rebuild the controller
Pick the Summer template closest to your genre. Give the agent the old controller code and your tuning table, have it rebuild the player, then run the game and compare movement against the recording until it feels the same.
- 5
Step 5: Rebuild one level, then the core loop
Get one complete level playing, with enemies, pickups and a win or lose state, before touching the rest. Then port scoring, progression, checkpoints and saving.
- 6
Step 6: UI, then content, then the changes
Rebuild menus and the HUD, then the remaining levels and content. Only when the remake matches the original should you add the new ideas from your one-sentence plan, so every change is a choice rather than an accident.
Two ways to run it
In Studio, or from the agent you already use
In Summer Studio
Summer Studio runs in the browser and makes the assets a remake often needs, higher resolution 2D art, 3D models as GLB files with auto-rigging for characters, sound effects, music and character voices. Download them or send them to your library, then import them into the project.
Open Summer StudioFrom Claude, Cursor or Codex via MCP
From Claude Code, Cursor or Codex, the Summer MCP gives your agent the same tools against the Summer desktop app. It can read the old project on disk as the spec, write GDScript, run the game with summer_play, drive it with summer_game_input and prove each result with a before and after summer_game_probe.
Example prompt for your agent
Read old/Player.cs and docs/tuning.md as the spec. In the open Summer project, rebuild the player controller with the same speeds and jump height, then run the game, script a standing jump with summer_game_input and report the apex height from summer_game_probe next to the value in tuning.md.Set up the Summer MCP
| Type | What changes | What stays | Example |
|---|---|---|---|
| Port | The platform | The engine, code and assets, with small fixes | A game moved to a new console with its original engine |
| Remaster | Many assets, resolution and convenience | Gameplay, very close to the original | The Legend of Zelda, The Wind Waker HD |
| Remake | Code, assets and often controls and design | The core story and gameplay ideas | Resident Evil 2 (2019) |
| Your remake in Summer | The engine, the code and any assets you choose | Your design, tuning values and owned assets | Your old game, rebuilt from its own spec |
Sources: Wikipedia, Video game remake
Examples
Prompts that work, and what comes back
Prompts for the agent at each stage of a remake. Each one produces something you can check against the original.
Tuning table
Prompt
Read every file in old/scripts and list each gameplay constant with its value, unit and where it is used, as a table in docs/tuning.md.
What you get
One document with the numbers that define how the old game feels, which becomes the spec for every rebuilt system.
Controller rebuild
Prompt
Rebuild the player from old/player.gml using docs/tuning.md. Convert per-frame values to per-second at 60 frames per second and run the game.
What you get
A player scene and script with the old values as exported variables, and a running build to compare with the recording.
Measured jump
Prompt
Run the game, script a standing jump, and probe the player's position every few frames. Tell me the apex height and time to land, and compare with the table.
What you get
Frame-stamped numbers that show whether the remake matches the original, instead of an opinion that it feels close.
Asset upgrade
Prompt
Recreate the old 32 by 32 slime enemy as a 128 by 128 hand-painted sprite with the same silhouette and colors, four-frame idle animation
What you get
New art that keeps the character readable to players who know the original.
First level parity check
Prompt
Play level 1 with scripted input that follows the recorded route, and report any point where the player gets stuck or the timing differs from the original.
What you get
A list of layout or tuning differences to fix before you move on to level 2.
Remake vs remaster, which one your game needs
A remaster stays very faithful to the original and upgrades mostly assets and convenience, the way The Wind Waker HD kept its look and play while sharpening the visuals. A remake rebuilds the game and may change how it plays, as the 2019 Resident Evil 2 replaced tank controls with an over-the-shoulder camera. A port moves the game to a new platform with its existing engine and assets.
Moving to a new engine means a rebuild either way, because the code does not carry over. The choice is about design. Choose a remaster if players loved the game as it was and you mainly want it to look and run better. Choose a remake if the core idea was good but the controls, pacing or scope held it back.
What to keep and what to let go
Keep everything that describes the game rather than the old engine. The design, the level layouts, the tuning values, the writing and the assets you own are the game. Players remember how a jump felt and how a boss moved, and those live in numbers you can copy exactly.
Let go of the old code's structure. Every engine pushes code into its own shape, with its own event order and workarounds, and translating that line by line imports old bugs into the new project. Use the old code to learn what it does, then rebuild the behavior the way the new engine expects.
- Keep the design notes, level layouts and tuning values.
- Keep art, audio and writing you own or license outside the old engine.
- Replace assets that are locked to the old engine or too low resolution.
- Drop engine workarounds, dead features and code structure.
- Write down any change you want before you start, and add it last.
Rebuilding is normal, even for hits
Vampire Survivors began in 2020 in Phaser, a JavaScript framework, and reached its full Steam release on that stack in October 2022. With version 1.6 in August 2023 its team moved it to Unity, and the announcement promised better cross-platform support and big performance improvements. The game players knew stayed the same while the engine underneath changed.
That is the goal of a good remake. The player should notice what you chose to improve, not what the new engine changed by accident.
The playtest loop
Test after every system, not at the end. Run the game, act, and check the result against the original. With Summer the agent can do the mechanical part, starting the game, sending scripted input, and reading the player's position, state and a screenshot on the same frame before and after. You look at the numbers and the screenshot and decide whether it feels right.
Keep a short list of parity checks, such as jump apex, run speed, dash distance, enemy reaction time and time to clear level 1, and rerun them after each change. When a later system breaks the feel of an earlier one, you find out in minutes instead of at release.
Guides for your old engine
The rebuild order is the same everywhere, but the concept map depends on where the game started. The three.js guide covers scene graphs and render loops, the GameMaker guide covers objects, alarms and Draw events, and the Godot publishing guide covers bringing an existing Godot 4 project into Summer.
Where to take your remake next
Port it to make money
A remake is a new release, so it can have its own store page. On Steam that means a desktop build, a Coming Soon page for at least two weeks, and a Steam Direct fee of 100 US dollars per game, paid back after the game earns 1,000 US dollars in adjusted gross revenue. itch.io is a fast second store.
How to publish a game on SteamRelease it on Summer Games
Summer Games is a new store for games made with Summer. It is launching soon. A remake built in Summer, reviewed, and working as a single-player game first is the kind of game that will be ready for it.
See Summer Games (launching soon)Grow it
A remake has an audience already. Tell the players of the original first, show old and new side by side in the trailer, open the store page early so wishlists build, and send it to creators who covered the first version.
Market your indie gameStart the remake
Pick the Summer template closest to your genre, bring in the assets you own, and give the agent your old code and tuning table as the spec for the controller. Playtest it against the original before you rebuild anything else.
Browse Summer templatesFrequently asked questions
What is the difference between a remake and a remaster?
A remaster stays very faithful to the original and mostly upgrades assets and convenience, as The Wind Waker HD did. A remake rebuilds the game and may change how it plays, as the 2019 Resident Evil 2 replaced tank controls. A port moves the game to a new platform with its existing engine and assets.
Should I remake my first game?
Often, yes. The design is already proven, you know its flaws, and the scope is known. Keep the remake close to the original first, then add a small number of planned improvements. Avoid turning it into a sequel halfway through.
Can I remake my game in Godot?
Yes. Godot 4 and Summer, which is compatible with Godot 4, import glTF models, common image formats and WAV, Ogg Vorbis and MP3 audio, so your assets move in directly. The logic is rebuilt in GDScript, one system at a time. The guides for three.js, GameMaker, Unity and Unreal map each engine's concepts to Godot.
What can I reuse from the old project?
Design notes, level layouts, tuning values, writing, and any art and audio you own or license for use outside the old engine. glTF models, PNG and JPG textures, and WAV, Ogg Vorbis and MP3 audio import directly. Code is rebuilt, not copied.
Can I remake a game someone else made?
Only with the rights to it. A remake of someone else's game uses their design, characters and often their name, so you need permission from whoever owns them. Remaking your own game, or a game you hold the rights to, avoids that problem.
How long does it take to remake a game?
It depends on the size of the original and how much you change. Rebuild the player controller first and time it. That tells you more than any estimate, because the controller shows how fast your old code turns into working systems in the new engine. Keep the first pass faithful, since every new idea added during the rebuild extends it.
How do I know the remake feels the same?
Measure it. Record the original, write down its tuning values, and have the agent run the remake with scripted input and report positions and timings from summer_game_probe. Compare jump height, speeds and timings, then fix the differences before moving on.
Related tools and guides
Sources
- Wikipedia, Video game remake
- Wikipedia, Vampire Survivors
- GamingOnLinux, Vampire Survivors switching to new game engine on August 17 (2023)
- Godot docs, Available 3D formats
- Godot docs, Importing audio samples
- Steamworks, Steam Direct fee
- Steamworks, Coming Soon page
- Unreal Engine docs, Quixel Bridge plugin (Megascans as UE-Only Content)
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