xbill for Google Developer Experts

Posted on Jun 5

Midsommer Madness

#devchallenge #gamechallenge #gamedev

June Solstice Game Jam Submission

This is a submission for the June Solstice Game Jam

What I Built

When it comes to Summar Solstace - the place to be is Sweden. It is one of the highlights of the calendar.

This project aimed to recreate some of the mystic around the event- just in time for some fresh surestromming!

Code

GitHub repo is here:

https://github.com/xbill9/midsommer-madness

xbill9 / midsommer-madness

Midsommer Madness - Swedish retro arcade game

Midsommer Madness 🇸🇪

Midsommer Madness is a Swedish-themed action retro arcade game inspired by Redneck Rampage and the Swedish Midsummer holiday.

Help Sven race against the solar timer to reach the Maypole (midsommarstång) before sundown! If you fail, the solstice is lost, you trigger a meltdown, and you are sacrificed to the Wicker Man.

📸 Screen Gallery

Title Screen	Game Over Screen	Victory Screen

🎮 Level Sequence

The game features ten distinct thematic levels:

IKEA Warehouse: Battle crowded, flatpack-carrying shoppers who throw box projectiles at you.
Systembolaget: The state-owned liquor shop crowded with drunk Swedes stumbling and lobbing green beer bottles.
Lördagsgodis: Sugar rush Saturday! Dodge hyperactive, strung-out Swedish kids throwing sweet candy projectiles.
The Swedish Pub: Sing along with Frank Zappa fans singing "Bobby Brown" (shouting and firing glowing letters B, O, B, B, Y).
Volvo Highway: A survival lane-crossing level where…

View on GitHub

This is Fun! How do I add my own levels?

> add a godis level where strung out kids throw lordagsgodis

▸ Thought for 2s, 525 tokens
  Considering Level Placement
  I will search for level ID checks referencing level 9 in game.js to prepare for adding a 10th level.

● Search(Search for lvl.id === 9 checks) (ctrl+o to expand)
  I will view lines 495 to 585 in game.js to inspect the current level configurations.
● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)
▸ Thought for 2s, 1.8k tokens
  Sequencing the Levels
  I will view the  setLevelAudioMode  method in game.js to prepare for adding Level 3 "Lördagsgodis".
● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will update the  setLevelAudioMode  method in game.js to map the scales and tempos for the 10-level
  layout.
● Edit(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)
  I will view the current level checks in  tickSequencer  inside game.js to prepare the next set of
  replacements.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will shift the level conditionals in the music sequencer  tickSequencer  method to accommodate the 10-level
  progression.
● Edit(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)
  I will view lines 920 to 935 of game.js to locate the exact Maypole check in  initLevel .
● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 1060 to 1070 of game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 1290 to 1300 of game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 1360 to 1375 of game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 1370 to 1385 of game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 1460 to 1475 of game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will update the level ID checks for the final Maypole level from  9  to  10  and register the candy-throwing
  kids target name in the HUD.
● Edit(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)
  I will view the start of the  levels  array in game.js to prepare the level insertion edit.
● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 545 to 585 of game.js.
● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

▸ Thought for 3s, 1.2k tokens
  Refining The Level Design
  I will update the  levels  array in game.js to insert Lördagsgodis as Level 3, shift subsequent level IDs,
  and re-calculate scores.
● Edit(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)
  I will view lines 950 to 985 of game.js to locate the  spawnEnemy  switch statement.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will view lines 985 to 1010 of game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will add the  "kid"  case to the  spawnEnemy  switch block.

● Edit(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

▸ Thought for 3s, 2.1k tokens
  Considering Projectile Design
  I will search for  class ZappaFan  in game.js to locate a suitable place to insert  CandyKid  and         
  Lordagsgodis .

● Search(Search for ZappaFan in game.js) (ctrl+o to expand)

  I will view lines 2120 to 2145 in game.js.

● Read(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)

  I will insert the  CandyKid  and  Lordagsgodis  class definitions in game.js right after the  Drunkard 
  class.

● Edit(/home/xbill/midsommer-madness/game.js) (ctrl+o to expand)
  I will view lines 275 to 325 of index.html.

● Read(/home/xbill/midsommer-madness/index.html) (ctrl+o to expand)

  I will update index.html to add Level 3 Lördagsgodis to the sidebar levels tracker and update levels 4
  through 10.
● Edit(/home/xbill/midsommer-madness/index.html) (ctrl+o to expand)

  I will run a syntax check on game.js using node to ensure the new classes and level configurations are
  syntax-error free.

● Bash(node -c game.js) (ctrl+o to expand)
  I will view lines 20 to 45 of game_overview.md to inspect the levels sequence list.

● Read(/home/xbill/.gemini/antigravity-cli/brain/a...2ba-4622-b252-003672e1b73f/game_overview.md) (ctrl+o to expand)

  I will update game_overview.md to describe the 10-level layout including Lördagsgodis.

● Edit(/home/xbill/.gemini/antigravity-cli/brain/a...2ba-4622-b252-003672e1b73f/game_overview.md) (ctrl+o to expand)

  I have successfully added the Lördagsgodis level to Midsommer Madness, featuring hyperactive, sugar-rushed
  children throwing Saturday candy at Sven!

### Summary of Changes

Level Setup ( game.js ): • Inserted Lördagsgodis as game.js in the levels array, shifting following levels up to Level 10 (ABBA Disco). • Updated all final-level check logic throughout game.js from Level 9 to Level 10.
Added CandyKid & Lordagsgodis Classes ( game.js ):
• Defined game.js and game.js right after the Drunkard class.
• Behavior:
• CandyKid has high speed (1.8), low health (35), and throws sweets rapidly.
• Kids shiver/vibrate rapidly on screen to depict their extreme sugar rush.
• Lordagsgodis are fast-moving candy projectiles (round jelly drops, square sweet gel blocks, and candy
star crosses) that rotate in flight and come in a variety of bright colors.
Music & Audio:
• Modified game.js to include a happy, hyperactive 150 BPM C Major chiptune track for Level 3
(Lördagsgodis).
• Shifted level conditions in game.js to map Levels 8, 9, and 10 to their respective custom chiptune
hooks.
UI & Documentation:
• renumerated the sidebar tracker list in index.html to show the 10-level layout.
• Updated the level progression descriptions in game_overview.md.

All modifications have been validated and parsed successfully. You can preview and play the game locally at
http://127.0.0.1:8081.

How I Built It

First - let's give antigravity some skills:

npx antigravity-awesome-skills

# Antigravity CLI slash commands (agy): ~/.gemini/antigravity-cli/skills/<skill>/SKILL.md
npx antigravity-awesome-skills --agy
Need to install the following packages:
antigravity-awesome-skills@12.1.0
Ok to proceed? (y) 
Cloning repository…
Cloning repository at v12.1.0…
Cloning into '/tmp/ag-skills-smWfsY'...
remote: Enumerating objects: 7516, done.
remote: Counting objects: 100% (7516/7516), done.
remote: Compressing objects: 100% (5375/5375), done.
remote: Total 7516 (delta 694), reused 5837 (delta 675), pack-reused 0 (from 0)
Receiving objects: 100% (7516/7516), 33.68 MiB | 51.63 MiB/s, done.
Resolving deltas: 100% (694/694), done.
Note: switching to '43af20cbe0dc298c40ff709993d8b4f7b4a274b6'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false


Installing for 1 target(s):

Antigravity:
  Updating existing install at /home/xbill/.agents/skills…
  ✓ Installed to /home/xbill/.agents/skills

Pick a bundle in docs/users/bundles.md and use @skill-name in your AI assistant.

If Antigravity hits context/truncation limits, see docs/users/agent-overload-recovery.md

For the agy CLI slash-command menu, install the Antigravity CLI layout with --agy.

For clone-based installs, use scripts/activate-skills.sh or scripts/activate-skills.bat

For Antigravity 2.0, OpenCode, or other .agents/skills installs, prefer a reduced install with --risk, --category, or --tags to avoid context overload.

Example: npx antigravity-awesome-skills --path .agents/skills --category development,backend --risk safe,none
Cloning repository…
Cloning repository at v12.1.0…
Cloning into '/tmp/ag-skills-Qc4vHc'...
remote: Enumerating objects: 7516, done.
remote: Counting objects: 100% (7516/7516), done.
remote: Compressing objects: 100% (5375/5375), done.
remote: Total 7516 (delta 694), reused 5837 (delta 675), pack-reused 0 (from 0)
Receiving objects: 100% (7516/7516), 33.68 MiB | 37.49 MiB/s, done.
Resolving deltas: 100% (694/694), done.
Note: switching to '43af20cbe0dc298c40ff709993d8b4f7b4a274b6'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false


Installing for 1 target(s):

Antigravity CLI:
  ✓ Installed to /home/xbill/.gemini/antigravity-cli/skills

Pick a bundle in docs/users/bundles.md and use @skill-name in your AI assistant.

Restart agy and type /skills or /<skill-name> to load installed Antigravity CLI skills.

My meatballs are getting cold- get to work!

xbill@penguin:~/midsommer-madness$ agy

      ▄▀▀▄        Antigravity CLI 1.0.5
     ▀▀▀▀▀▀       xbill9@gmail.com (Google AI Ultra)
    ▀▀▀▀▀▀▀▀      Gemini 3.5 Flash (High)
   ▄▀▀    ▀▀▄     ~/midsommer-madness
  ▄▀▀      ▀▀▄
────────────────────────────────────────────────────────────
> use skills and @[game-design.md] to create a web based game
● Read(/home/xbill/.gemini/antigravity-cli/skills/game-development/SKILL.md)
● Read(/home/xbill/midsommer-madness/game-design.md) (ctrl+o to expand)

▸ Thought for 1s, 570 tokens
  Defining the Game's Identity
● ListDir(/home/xbill/.gemini/antigravity-cli/skills/game-development)
● ListDir(/home/xbill/.gemini/antigravity-cli/skills/game-development/web-games)
● Read(/home/xbill/.gemini/antigravity-cli/skills/game-development/web-games/SKILL.md)
● Read(/home/xbill/.gemini/antigravity-cli/skills/game-development/2d-games/SKILL.md) (ctrl+o to expand)

▸ Thought for 1s, 559 tokens
  Considering Web Development Tools

● ListDir(/home/xbill/midsommer-madness)
● Read(/home/xbill/midsommer-madness/GEMINI.md) (ctrl+o to expand)

▸ Thought for 2s, 1.6k tokens
  Defining the Game's Theme

● GenerateImage(midsommer_madness_title)
● Bash(cp /home/xbill/.gemini/antigravity-cli/brain/a4a875d3-a2ba-4622-b252-
003672e1b73f/midsommer_madness_title_178...)
● GenerateImage(midsommer_meltdown)
● Bash(cp /home/xbill/.gemini/antigravity-cli/brain/a4a875d3-a2ba-4622-b252-
003672e1b73f/midsommer_meltdown_17806875...)
● GenerateImage(midsommer_victory)
● Bash(cp /home/xbill/.gemini/antigravity-cli/brain/a4a875d3-a2ba-4622-b252-003672e1b73f/midsomme...) (ctrl+o to
expand)
▸ Thought for 5s, 1.2k tokens
  Structuring the Game

● Create(/home/xbill/midsommer-madness/index.html) (ctrl+o to expand)

▸ Thought for 11s, 320 tokens
  Designing the UI

● Create(/home/xbill/midsommer-madness/index.css) (ctrl+o to expand)

▸ Thought for 32s, 2.3k tokens
  Refining Game Design
● Create(/home/xbill/midsommer-madness/game.js)
● ListDir(/home/xbill/midsommer-madness)
● Bash(node -v && npm -v)
● Create(/home/xbill/midsommer-madness/package.json) (ctrl+o to expand)

▸ Thought for 1s, 969 tokens
  Defining Artifacts & Structure

● Create(/home/xbill/.gemini/antigravity-cli/brain/a4a875d3-a2ba-4622-b252-003672e1b73f/game_overview.md)
● Bash(npm run dev)
● Edit(/home/xbill/midsommer-madness/package.json)
● Bash(npm run dev)
● Edit(/home/xbill/midsommer-madness/package.json)
● Bash(npm run dev)
● Read(/home/xbill/.gemini/antigravity-cli/brain/a4a875d3-a2...b252-003672e1b73f/.system_generated/tasks/task-52.log)
● Edit(/home/xbill/.gemini/antigravity-cli/brain/a...2ba-4622-b252-003672e1b73f/game_overview.md) (ctrl+o to expand)

▸ Thought for 4s, 580 tokens
  Summarizing The Pixel Art
  I have created a fully featured, high-fidelity web-based game for Midsommer Madness based on your design document.

  Here is a summary of the project setup and the files created:

  1. Pixel-Art Screen Illustrations: Generated three stunning retro game screens (Title, Meltdown, and Victory)
  using AI generation tools and integrated them directly into the interface:
      • midsommer_madness_title.png
      • midsommer_meltdown.png
      • midsommer_victory.png
  2. Layout & UI: Created index.html containing sidebars for how to play, lore, glossary details, and a
  responsive glassmorphic game wrapper.
  3. Styling System: Created index.css utilizing an animated Swedish yellow/blue radial mesh background,
  premium geometry typography (Google Fonts Outfit & Press Start 2P), keyboard keycap styling, and CRT scanline
  visual overlays.
  4. Game Engine: Created game.js using professional 2D game-development patterns:
      • Fixed Timestep Rule updates physics and mechanics at a strict 60Hz.
      • Input Abstraction for movement and attacks (melee hockey stick, ranged Surströmming can).
      • Web Audio API Synth that procedurally generates retro sound effects and background music loops that change
      scale and tempo based on the current level.
      • Polished FX including screen shake, particle systems, and food pickup loops.
  5. Project Config: Generated a package.json to start a local static server.

  ### 🎮 Play the Game

  I have started the local development server in the background. You can open your browser and play the game right
  now:

  👉 http://127.0.0.1:8081

  For a full breakdown of the level designs, mechanics, and asset galleries, please check out the generated
  artifact:
  📄 game_overview.md

Prize Category

Best Google AI Usage - Antigravity CLI

DEV Community