The Real Build: Galaxy Defender, Prompt by Prompt

This is not a tutorial written after the fact — it is the actual transcript of prompts a real person typed (mostly voice-dictated, on a phone!) to direct an AI coding agent, one evening, from "there is no game" to the finished Galaxy Defender you can play right now — complete with original music, math-learning power-ups, unlockable ships, a voice countdown, and a public parents' scoreboard.

Read the prompts exactly as they were spoken — typos, autocorrect accidents and all ("timu Casino" was meant to be Temu / casino-style flashy, "Waze" meant ways). That's the first lesson: you don't need perfect prompts. You need a clear vision, delivered in small, honest pieces.

Prompt 1 — Start with the destination, not the directions

"Can you go to games.marcinmigdal.com and I want to create a brand new game on a path similar to where the monster truck is called Galaxy Defender. Arcade · Shooter — Defend the galaxy! Blast through endless waves of grinning cartoon alien invaders, scoop up power-ups, and survive escalating boss fights in a fast, colourful space shooter inspired by the arcade classics."

What the AI did: found the existing monster truck game on the server, copied its folder structure and design language, built a complete HTML5 canvas space shooter plus a marketing landing page, and flipped the homepage card from "Coming Soon" to live.

Prompting lesson: point at something that already exists ("similar to the monster truck") and describe the experience you want. The AI fills in a thousand technical decisions you never have to make.

Prompt 2 — Define the audience and the feeling

"I want you to treat this game for a 4 to 8 years old demographic and I want you to have very vibrant colors I want you to do some sound effects for shooting that are a psychologically addictive and the graphics that I want you to use are timu Casino very wow very amazing very brilliant and come up with your own versions of just hyped up messaging when you get a high score and come up with Waze where the user is penalized… maybe have three levels of how fast the aliens are coming or anything that is currently trending on Google Play and iOS store… just make this game the best game best game ever for the kids out there"

What the AI did: neon gradients and confetti everywhere, laser sounds with reward chimes that climb a musical ladder as your combo grows, hype banners ("UNSTOPPABLE!!!"), three speed levels (Cadet / Ace / Legend), and gentle penalties (combos break if you stop shooting; aliens that sneak past cost a heart).

Prompting lesson: audience + feeling beats feature lists. "For 4-to-8-year-olds, casino-bright, psychologically rewarding" gave the AI a north star for hundreds of small decisions.

Prompt 3 — Reference your own assets ("go listen to it")

"can we add a very melodic background catchy very memorable kids music very similar to the ones that we use for the monster truck game that's also on the same server so look it up listen to the track and try to create something similar… each level should have its own track as well"

What the AI did: identified the monster truck's track from its MP3 metadata ("Monkeys Spinning Monkeys" by Kevin MacLeod, 144 BPM), then composed six original tunes in the same bouncy style using the browser's audio synthesizer — a different song for every wave, a boss stomper, and a gentle menu tune. Zero copyright risk, zero downloads.

Prompting lesson: the AI can inspect what you already have. "Look it up and make something similar" is a legitimate, powerful instruction.

Prompt 4 — Ask for the critique, not just the work

"I want you to play Devil's Advocate and how else we can make this game rank number one on Google store and iOS… maybe we can get parents to have some sort of a mapping scoring system within the game if you do 2 + 1 you get extra points give me some ideas of how we can make this game more sellable and marketable to parents and kids"

What the AI did: delivered an honest teardown (no persistent progression, no daily return hook, browser games don't rank in app stores without wrapping) plus a roadmap. The throwaway "2 + 1 = extra points" idea became the game's signature feature.

Prompting lesson: "Play devil's advocate" flips the AI from builder to critic. Some of your best features start as half-sentences inside a brainstorm request.

Prompt 5 — Show pictures, ask "new thing or this thing?"

(with a reference image of cute cartoon dinosaurs) "is there any way that you can think you can incorporate cute faces of dinosaurs into the game… maybe throwing some sort of Nets over the dinosaurs we wanted to have kid-friendly we don't have any violence or maybe we're inviting the dinosaurs into a Jurassic Park… let me know if this is maybe a new game or if you can find a way to incorporate this idea into this game"

What the AI did: recommended keeping the brands separate — a future stand-alone "Dino Rescue Ranger" (nets, treats, and a sanctuary you build; zero violence) instead of cramming dinosaurs into a space shooter.

Prompting lesson: you can hand the AI a picture and an open question. Asking "should this be a new thing?" invites judgment, not just obedience.

Prompt 6 — The big feature drop (one breath, five features)

"Okay let's start with the brain boost… maybe have some sort of a quick fancy colorful landing almost like a space garage so they know what to look forward to also incorporate the idea of before you start the game ask what is your name starfighter? And then incorporate the name of the person… additionally incorporate that extra page and give me the link to it so parents can log in I don't know if we need the login for that. Maybe make it publicly available but don't ask for last name so that way any parent can go on there and compare their kids scores with other scores and make the whole page feel very friendly as well like the game"

What the AI did: math-question bubbles you shoot for bonuses (every third correct answer restores a heart), six unlockable ships in a neon Space Garage with a landing animation, "What's your name, Starfighter?" used throughout the game, a tiny score-saving backend, and the public no-login parents page — first names only.

Prompting lesson: thinking out loud is fine ("I don't know if we need the login for that") — the AI resolves your open questions with sensible defaults you can veto later.

Prompts 7 & 8 — Small asks are still asks

"I want you to add a button to mute the sound and exit the game to the level section" … "So let's just add that in"

What the AI did: floating mute and exit buttons during gameplay. Ten words, one feature.

Prompting lesson: not every prompt needs to be a paragraph. Keep a running conversation and toss small fixes in as you notice them.

Prompt 9 — Delegate the thinking, in parallel

"Let's spin another agent and I want you to tell me your opinion on having Level versus a selection 1 minute 3 minute 5 minutes like we do on Monster Truck Hilltop Rally"

What the AI did: launched a second AI agent to analyze the design question while the first kept coding. Verdict: hybrid — timed sessions as the container (parents love a hard stop), waves and bosses as the content inside.

Prompting lesson: AI agents can run in parallel. Send one off to research or deliberate while another builds — like having a team.

Prompt 10 — Tune the difficulty with feelings, not numbers

"I also want the alien heads to come down little faster I want them to vary so some colors will go down fast than others to try and sneak past it's right now a little too easy… also maybe some are a little more angry and then they have some Fireballs or they're also shooting down lasers so that way the ship has to avoid them as well"

What the AI did: gave every alien colour a personality — zippy cyan sneakers, big slow pinks that take extra hits, and angry red ones (with eyebrows!) that hurl fireballs you must dodge or shoot down.

Prompting lesson: "it's a little too easy" is a perfectly good spec. Describe the play-feel you want; let the AI translate it into speeds and spawn rates.

Prompts 11 & 12 — Reuse what works, then trim it

"Monster truck has some sound effects… it says get ready get set go I want you to steal that same exact sound MP3… don't immediately start… just pause the game play the MP3 and then after the Starfighter game should start" … "If the get ready get set go MP3 has something else in front of it I want you to cut that… just cut that and use Get Ready Get Set Go"

What the AI did: reused the announcer clip, discovered from the monster truck's own code that the voice starts 3.2 seconds in, trimmed the 20-second file down to a tight 4.7-second "GET READY… GET SET… GO!!", and synced on-screen words to the voice while the game holds at the start line.

Prompting lesson: you predicted a problem ("if it has something in front of it") before hearing the file. Sharing your suspicions saves a whole feedback round-trip.

Prompt 13 — Turn the work into an asset

"Spin out another agent and I want you to take every single user prompt that I've created here and I want you to save it and turn it into a lesson…"

What the AI did: the page you're reading.

Prompting lesson: your prompt history is intellectual property. One session of honest prompts became a game and a lesson.

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Part 2 — The Polish Session (prompts 14–18)

A week of play later, the builder came back — from a phone, between other projects — and turned a working game into a delightful one. Same rules: short, honest, voice-dictated prompts, typos left in.

Prompt 14 — Give the garage a voice

"When you enter the garage have it says mp3 'your garage only has 1 spaceship! there are 5 more waiting to be unlocked! complete your missions and come back to unlock them!. lets go get those aliens!'. then create a different fun varient for each of 6 depending on how many are unlocked."

What the AI did: wrote six escalating announcer lines (one per garage size, ending with "Six out of six! Your garage is complete, captain!"), generated them as MP3s with an AI text-to-speech voice directed to sound like a cartoon mission commander, and wired the right clip to play every time the garage opens.

Prompting lesson: give one finished example and ask for "a fun variant for each state." You write one line; the AI writes the other five in the same voice.

Prompt 15 — Redesign a whole mechanic in one breath

"Make the 3 plus two letters even larger make sure they still fit on the screen Do not allow the Starfighter to shoot . The user must tap o. th3 correct answer in order to shoot at that. So when the user presses 6 for example . the spaceship will move Beneath and shoot at the six . and we want claps playing as well. then flash the math equation in full screen large letters and repeat it so kid understands whst they did. 'thsts corecr! 3 plus 2 equals 5' do another cheering sound wffedr and then animate out and back into rhe alien game."

What the AI did: five changes from one prompt — a bigger shrink-to-fit equation, free shooting disabled during math, tap-an-answer controls where the ship glides under the tapped bubble and fires a homing shot, a claps-then-spoken recap ("That's correct! 3 plus 2 equals 5") flashed full-screen in giant letters, and a zoom-out animation back into the battle. It also generated the new voice clips the recap needed.

Prompting lesson: describe the sequence the player experiences, beat by beat ("when the user presses 6… the ship moves beneath… claps… then flash…"). A storyboard in words is the best spec there is.

Prompt 16 — Name the annoyance precisely

"When the math problem mini game comes in Make sure that the MP3 audio doesnt conclicz with oghers. so If you shoot the correct answer make sure that it right away stops with the first MP3 … cuz right now if you get the right answer right away it keeps playing the first audio which is annoying"

What the AI did: made the voice channel exclusive — the instant a correct answer lands, the still-talking question audio is hard-stopped before the celebration begins, and every other voice moment (garage, question, recap) claims the mic the same way.

Prompting lesson: "which is annoying" is real user research. Reporting exactly when the bad thing happens ("if you get the right answer right away") hands the AI the reproduction steps.

Prompt 17 — Screenshot + one sentence

"Some of the words are cut off as you can see so make sure that they're stacked or wrapped on the lines"

What the AI did: the "FINALE BOSS!! TAKE IT DOWN!!" banner was wider than a phone screen. Banners now word-wrap into stacked lines and shrink to fit, so no message ever runs off the edge.

Prompting lesson: a screenshot plus one sentence beats three paragraphs of description. "As you can see" works when the AI literally can see.

Prompt 18 — Verify like a player

"Is the audio inside the garage done? I go into the garage i dont hear how many i have"

What the AI did: confirmed the feature was live on the server, then found the real culprit — the browser had cached the old game page — and fixed the root cause by telling the server to never let game HTML go stale, so every future fix reaches players on their next launch.

Prompting lesson: test like a player, report what you experienced, and don't accept "it works on the server." The gap between "deployed" and "what's on my phone" is a real bug class of its own.

Prompt 19 — Cut what you hate

"remove yey, whohoo yea mp3 it spunds awful"

What the AI did: found the "woohoo, made it!" voice clip among forty audio files, removed every place the game played it, and swapped in the crowd-cheer that was already working — live within a minute.

Prompting lesson: taste is a spec too. You don't have to justify "it sounds awful" — naming roughly what you heard is enough for the AI to find the exact file.

Part 2 takeaways

1. Polish is prompts too. The jump from "works" to "wow" was five more honest asks.
2. Storyboard the player's moment and the AI will build the mechanic, the art, and the sound to match.
3. Annoyances are specs. "It keeps playing and it's annoying" fixed an audio architecture.
4. Close the loop on devices you own. If you can't hear it on your phone, it isn't shipped yet.

The six takeaways

1. Vision first, details later. Audience + feeling + a reference point beats a technical spec.
2. Iterate in small honest asks. Thirteen short prompts, each shippable on its own.
3. Point at what already exists. "Like the monster truck" did more work than any adjective.
4. Ask for criticism. The devil's-advocate prompt produced the game's best feature.
5. Delegate in parallel. Spin off agents for research while the build continues.
6. Don't fear typos. Voice-dictated, autocorrect-mangled prompts built a polished game. Clarity of intent beats polish of prose.

Want to build your own? Start with the first lesson of this course — or just open a chat and describe the game you wish existed.