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A fixed shooter is built around a simple threat: enemies sweep across the screen, step downward, and gradually take away your safe space. That format stays appealing because the rules are easy to grasp while the pressure curve gets sharper every few seconds. This browser Space Invaders game turns that classic pattern into a quick run-based score chase with clear feedback after every attempt.
You choose a difficulty, start the round, and keep one ship alive long enough to break apart wave after wave of descending invaders. The playfield keeps four numbers in view the whole time: score, lives, level, and best score. That makes each run feel measurable, not vague, because you can immediately tell whether a new attempt was safer, longer, or more productive than the last one.
The package is tuned for short sessions rather than long progression. There are no menus full of upgrades, no inventory system, and no campaign structure to remember when you come back later. What matters here is movement, timing, and reading the formation before it traps you near an edge.
That focus is important because the pressure does not come from several enemy systems layered together. In this build, the invaders do not fire back. Instead, danger comes from their sideways sweep, their downward step when they hit a boundary, and the moment any invader drops below your ship's row. The game rewards staying one decision ahead of that march.
The implementation is also intentionally local. A browser with working WebGL support is needed for the 3D playfield to render, the best score is stored only in local browser storage, and the end-of-run summary exports are generated on the device. There is no shipped backend score sync, account system, or remote leaderboard in this package.
Difficulty is the first practical choice. Easy gives you the gentlest opening pace and is the best place to learn the rhythm of edge bounces and level resets. Medium is the default balance point. Hard starts with much faster horizontal pressure, so it is less about learning the rules and more about testing whether your lane-clearing habits still hold when the formation moves sooner than you expect.
The second choice is control style. Keyboard movement is explicit and predictable, which helps if you like tapping into position and firing in short bursts. Mouse control feels looser because the ship eases toward the pointer location instead of snapping there instantly. The game also tracks the last input source, so the control indicator becomes a useful reminder of how you were actually playing during the run that just ended.
Most mistakes happen near the sides. If you drift too far left or right without a clear exit, the next downward step can remove the room you thought you still had. A better habit is to carve a lane, keep the ship near the next escape route, and treat every shot as part of positioning rather than as pure aggression. The safest run is often the one where you spend slightly less time firing and slightly more time preserving movement space.
Pause and fullscreen matter more than they might seem in a small arcade game. Pause lets you break the loop before a rushed decision becomes a lost life, while fullscreen gives the playfield more visual breathing room when you want cleaner tracking on a larger display. After a run ends, the summary table gives you a compact review you can copy row by row, copy as CSV, download as CSV, or export as a DOCX report for later comparison.
The wave structure is straightforward and consistent. Every level uses seven columns of invaders. The opening wave starts with three rows, and each new level adds one more row. Because every defeated invader is worth 10 points, the score value is tightly linked to how much of a wave you actually cleared rather than to hidden bonuses or multipliers.
| Rule | Meaning |
|---|---|
rows = level + 2 |
Level 1 starts with 3 rows, level 2 with 4 rows, and so on. |
invaders = 7 × rows |
Each wave always uses 7 columns, so row growth directly increases total targets. |
score = 10 × defeated invaders |
There are no variable enemy point values in this package. |
Difficulty changes the opening speed of the two things that matter most: how quickly your shots travel upward and how quickly the formation begins its horizontal sweep. Level progression then adds another pressure step by increasing invader horizontal speed after each full clear. The result is a game that starts readable and becomes less forgiving without changing the core rules.
| Difficulty | Bullet speed | Opening invader speed | Practical effect |
|---|---|---|---|
| Easy | 0.10 | 0.008 | Best for learning the sweep pattern and recovery timing. |
| Medium | 0.12 | 0.010 | Balanced pace for repeat score attempts. |
| Hard | 0.15 | 0.020 | Fast early pressure with less room for indecision. |
Life handling is equally clear. You start every run with three lives. If any invader drops below the ship's row, you lose one life, the ship recenters, all bullets are cleared, and the current wave is rebuilt. If that loss takes lives to zero, the game ends immediately, writes the score into the local best-score record if it is a new high, and generates the summary table shown beneath the playfield.
Shots always travel straight up from the ship's current position. Mouse input changes where the ship is, not the angle of the projectile. Keyboard movement shifts the ship in fixed steps, while mouse control eases toward the pointer for smoother horizontal tracking. Under the hood, hit detection uses object-bound intersections, but that technical detail mainly matters because it explains why close calls feel visually fair: a hit comes from overlap with the rendered object, not from an invisible score zone.
The visuals add variety without changing the scoring model. Invader shapes and colors are randomized from a small set of geometric forms, there is a starfield backdrop, and hits create particle bursts, but none of that alters point value or enemy durability. The only persistent state saved between sessions is the best score, stored in local browser storage. Everything else resets when you restart a run.
A good first benchmark is not a giant score. It is finishing the opening wave cleanly enough to reach level 2 while still feeling in control of your movement space.
The run summary is small, but each field tells you something specific about how the attempt unfolded. Score is the cleanest indicator of how much of the formation you actually removed. Best score is the highest total stored on the current browser and device, so it is useful for personal practice tracking but not for cross-device comparison.
Level reached is the wave number you were on when the game ended, which is not exactly the same as the number of levels fully cleared. If you lose on level 3, the summary still records level 3 because that was the active wave at the point of failure. Control mode reflects the last input method used, which helps explain why two runs with similar scores may have felt different in hand.
Run duration is formatted as minutes and seconds from the moment the round starts. Lives remaining is included for completeness, but because the summary is generated only at game over, that value will normally be zero. In practice, the most useful comparison set is score, level reached, control mode, and duration together rather than any one number in isolation.
Opening clear on level 1. The first wave contains 3 rows and 7 columns, for 21 invaders total. Clearing all of them gives 210 points and advances you to level 2, where the wave resets with one extra row and a faster horizontal sweep.
Pressure jump by level 3. By level 3 the wave contains 5 rows, or 35 invaders. A perfect clear there is worth 350 points, but the more important change is spatial: the extra rows make it easier to get pinned under the formation if you let the sides close in.
Hard-mode comparison. Hard still begins with 21 invaders in the first wave, so the scoring math does not change. What changes is the speed at which the formation reaches an edge and drops. If your score falls on Hard, it usually reflects less time to reposition, not a different points table.
No. Shots always travel straight upward from the ship. Mouse input changes the ship's horizontal position and lets a click fire from that current position.
No. The shipped code stores only the best score in local browser storage and generates exports locally.
The ship is recentered, bullets are cleared, and the current wave is rebuilt. If that was your last life, the round ends instead.
No. This package focuses on downward wave pressure, scoring, and movement timing rather than on shield management or return fire.
It needs a browser and device that can create a WebGL scene. If WebGL cannot be created, the playfield will not render as intended.
Pause only suspends the current session. The package does not save in-progress runs for later restoration.