Sky Fighter

The sky, and how a run ends

The board is 360×640 units. Your fighter flies freely — up, down, left and right — through the lower sky, below the band where enemies enter, and enemies come from the top a wave at a time. Which formations enter comes from a fixed seed together with the stage and wave number, so every player meets the same waves on the same stage, and a golden test keeps them that way.

• A run is one attempt: it starts at the stage you pick, and every stage you clear rolls straight into the next. Your upgrades and lives ride along inside the run — and never leave it.
• Cleared: stage 100, the final boss, goes down. The run is complete.
• Failed: you lose your last life. The stage you reached and your score remain.
• A stage you clear is unlocked and saved the moment it happens, even if the run ends one wave later.
• Between waves there is a quiet beat of 0.9 seconds, and your guns stop during it. It is a breath, not a countdown.

Controls

• Drag to fly. Your fighter follows the movement of your finger — relatively, so touching the far side of the board never teleports the ship — and the four arrow keys work too.
• Firing is automatic and always on. There is no fire button anywhere in the game.
• That is why moving is aiming: the only decision the controls ask of you is where to be.

One gesture and no fire button is what makes this playable with a thumb on a bus. It also means nothing on screen has to explain itself in fourteen languages.

Six silhouettes, and what a hit does

There are six kinds of enemy and you tell them apart by silhouette — all of them fly nose down. Size decides how much a craft can take and what it pays; the kind decides its shape, its gun and the way it flies.

• Bomber — large. Fires single shots straight down. Downed, it splits into 2 fighters.
• Heavy bomber — large and thick. Drops a three-shot curtain, and it is the one exception to a quieting cascade: downed, it splits into 2 gunships.
• Fighter — medium, unarmed. Splits into 2 scouts.
• Gunship — medium, a little thick, and it aims at you. Splits into 2 scouts.
• Scout — small, unarmed, one shot and gone. Scouts only come from splits — the stage never sends one.
• Darter — small, unarmed, and it comes to you: it drifts toward your ship as it dives, but clearly slower sideways than you fly, so it can always be dodged.
• Waves send five of the six kinds. Bombers, fighters and gunships fly from stage 1, darters join at stage 3, heavy bombers at stage 8.
• An enemy that gets past you costs you nothing but its points. It simply flies away; it does not take a life.
• Touching one does: a life goes and you get 1.2 seconds of invulnerability, shown as a blink. Your upgrades stay.

Within a cascade, the smaller the craft, the more it scores — a bomber pays 10, the fighters it becomes pay 20 each, the scouts after that 30. The two large kinds also grow tougher as stages climb; scouts and darters stay one-shot kills for the whole hundred.

Three of the six shoot back

• Bombers, heavy bombers and gunships are the armed kinds. Everything a bomber or a fighter splits into is unarmed — but a heavy bomber splits into gunships, so it is the one craft that can be worth leaving whole.
• The gunship is the reason to keep moving: its shots are aimed at where you are. Not perfectly — each craft skews its aim a fixed way, so a line of gunships never converges on one point.
• Enemy shots are slow: 175 against your own 540. They are meant to be stepped around rather than reacted to.
• Each kind has its own firing rhythm — gunships shortest, heavy bombers longest — staggered per aircraft so a formation never fires as one, quickening as stages climb, and never faster than a fixed floor.
• A craft still above the top edge of the screen does not fire.
• Being shot is treated exactly like being touched: one life, the same 1.2 seconds of grace, and your upgrades untouched.
• Enemy shots are drawn as long tracers along their flight, so they never look like your own round ones.

Crates, hearts and the four ways you get stronger

Your weapon grows along four independent axes, and every step comes from something you caught in the air. Power makes each shot hit harder. Rapid shortens the pause between shots. Spread adds barrels, from a single gun to five in a fan. Missile adds homing missiles that lock onto the nearest enemy the moment they launch. Each axis has its own cap, and the HUD folds the whole arsenal into one short line — P2 R1 S3 M1.

• Only the smallest craft — scouts and darters — can drop something, decided per enemy from the run's own seed: the same stage can pay out differently on the next run. Only one drop is ever falling at a time.
• A weapon crate looks like a miniature of your own fighter. Catch it and one axis that still has room grows by 1 — the game picks, a short toast tells you which, and if every axis is full the crate turns into points instead.
• A heart restores one life, never past your maximum. A Max Life — the rarer, larger heart with a cross — raises the maximum itself, up to 6, and fills the new slot. It mostly comes from bosses.
• Lives and weapons are separate ledgers. Catching a crate never heals you, and losing a life never dulls your guns.
• Upgrades are free, earned in play, capped, and reset with the run. There is no currency, no permanent growth, and nothing here is ever sold.

The 100 stages, the bosses and the help you get

A stage holds 4 to 6 waves, later stages are faster and busier, and a run can start from any stage you have already cleared. Every tenth stage is a boss. Instead of waves, one large machine descends — with its own health bar at the top of the screen, in the band your ship cannot enter.

• Three bosses take turns: a fighter that sweeps quickly and fires aimed fans, a bomber that drifts slowly behind a curtain of shots, and a carrier that keeps launching darters at you, two at a time. Stage 40's fighter is not stage 10's — every boss lever grows with the stage, and nothing in the ladder saturates before 100.
• Beating a boss opens a choice of up to three upgrades. The game stands completely still while you decide — no timer, and no ad. The choices never repeat each other, axes already at their cap are never offered, and a fully grown ship is offered repairs and points instead.
• Best score is one number for the whole game, not one per stage. A score is what a run earned, so the points from a run you lost still stand — you shot what you shot.
• There is no Undo and no Hint: the sky moves in real time and nothing is hidden for a hint to reveal.
• The help is an instant, free retry, the grace period after a hit, the enemies that cost only points when they slip past — and the bosses themselves, whose rewards are where most extra hearts come from.
• There is no continue to watch an ad for and no extra life to buy. There is also no mid-run save — leaving the game screen discards the attempt, while your statistics, your best score and your unlocked stages are always kept.

Statistics are runs, stages cleared, best score and total play time. No streaks, and no online ranking — a leaderboard is a server someone has to keep paying for.

Questions people ask