Invaders from the Third Dimension

Invaders from the Third Dimension is a shoot ’em up in which you rotate your ship to aim and fire at enemies entering from the top of the screen. The landscape layout combines horizontal and vertical shooting: you can aim from forward to sideways, including diagonally, instead of only moving horizontally and firing vertically. Rotating also lets you vary your horizontal speed and angle your ship through gaps between bullets.

Enemies and weapons

Enemy positions are randomized, and enemies use AI to decide where to move and when to shoot. Each level introduces a new enemy with a new weapon. Enemy weapons include lasers that move quickly but deal little damage, splitting bullets that cover a wide area but leave gaps, and rockets that can be shot down but deal heavy damage if they hit. The final level adds heat-seeking rockets.

Upgrade your ship

You start with a single semi-automatic laser cannon. Taking out enemies gives you opportunities to collect power-ups, including additional laser cannons, bursts of automatic fire and eventually full auto. Halfway through each level, your health bar grows so you can take on more powerful enemies.

Visuals and sound

Ships rotate in 3D, enemies move in circular patterns and perform barrel rolls, and laser beams glow and illuminate their surroundings. Explosions use particles and smoke. The game runs at 60 FPS with v-sync and includes an 80s-style synthwave soundtrack.

Controls and saving

You move and shoot. The game automatically saves your progress at the start of each level.