Space Alien Invaders
Free arcade style space shooter game for the PC.
http://www.freewareshareware.net/download/sai.exe - 1Mb - Download - Screenshot

Cash Invaders
Cash Invaders is a space shooting game for MS-DOS. You shoot aliens to earn money, with that money you can buy power-ups. There are 100 levels plus 9 bonus levels. The game mixes elements from Space Invaders, Blood Money, SpaceBastards and some other games. ... All graphics are raytraced with 3D Studio Max.
http://members.home.nl/bas.de.reuver/cashinvaders/invader.zip - 416Kb - Download - Screenshot

Typing Invaders - Free Typing Game
Typing Invaders is a REAL arcade game, in which you are escaping from invaders, shooting and trying to hit invaders. This is no fake - you are playing space invaders ! (You are not just typing characters). With this free typing game you WILL have fun, but don't worry, by playing Typing Invaders... Improve your typing skills with this free typing tutor - typing game !
http://www.giletech.net/Typing-Tutor/TInv_Setup.exe - 1Mb - Download - Screenshot

Alien Invaders Attack!
Free arcade style space shooter game for the PC.
http://www.sci-fi-game.com/download/aia.exe - 4Mb - Download - Screenshot

Star Reaver
Star Reaver is a freeware arcade style space shooter game, available for free download. Defend your ship from dive bombing alien space invaders. Grab the power ups for powerful new multi-directional weapons that shred the marauding invaders. Free download available for PC and Mac.
http://www.freewareshareware.net/download/sr.exe - 2Mb - Download - Screenshot

Invasion 3D
Invasion 3D is a free multi-platform 3D arcade game, based on OpenGL and SDL and available for Windows and Linux. This fun and addictive game features realistic physics simulation, challenging gameplay, stunning visual effects,multiple weapons, hidden bonuses, and more. ... Invasion 3D was Inspired by Taito's original Space Invaders arcade game from 1978, and is dedicated to the MAME arcade emulator system. ... Create massive destruction and rack up as many points as you can as you blast your way through 20 waves with thousands of aggressive space invaders!
http://www.fascinationsoftware.com/FS/media/Invasion3D.tar.gz - 2Mb - Download - Screenshot

Da Browser Based Games Browser
Da Browser Based Games Browser is a custom games web browser that delivers easy navigation to arcade classics (Pac Man, Tetris, Asteroids, Space Invaders, etc), browser based games, browser based game websites, and web game directories. The distinctive feature of Da Browser Based Games Browser... Da Browser Based Games Browser will simply provide easy access to thousands of web games to the web games enthusiast. ... In addition, Da Browser Based Games Browser is equipped with an integrated search engine utilizing the popular search engines and allows you to save and access your favorite...
http://www.4comtech.com/vb/gamesbrowsersetup.exe - 2Mb - Download - Screenshot

Jumpix
The XXII century. Our Earth is in danger. The invaders want to capture it and make their colony. For a long time the Earth was covered with a protective sphere. But the invaders have invented new weapons to destroy the protective sphere. The only chance to protect the Earth is to use a... You are given an opportunity to defeat of the invaders and get to the Space Intellect. ... Welcome to the board the space fighter and follow some instructions to control this machine. ... Turn to this thrilling game, its beautiful graphics,thrilling music tracks,Interesting helpful bonuses...
http://www.gamexzone.com/files/jumpix.exe - 3Mb - Download - Screenshot

When Icons Attack
Your desktop icons are on a rampage. They have gone wild and are attempting to seize control of the desktop. Only one obstacle stands in there way -- you! This exciting space shooter features over 100 unique levels and rendered graphics. The game plays a bit like space invaders, with some galaga... Play the game with mouse, joystick, or keyboard. ... 0. ... Only you can stop the icon invaders. ... Requires DirectX 9. ... The icons, of course, have been augmented with powerful weapons of their own, and it will be very challenging to defeat them all.
http://www.sb-software.com/wheniconsattack/sbicon11.exe - 3Mb - Download - Screenshot

Dylo's Adventure - Windows
An old-school platform game where Dylo -a groovy dinosaur- gets involved in the adventure of ruining the twisted plans of the evil space invaders who want to conquer planet Earth and turn it into their own theme-park. Only armed with stones and boomerangs, Dylo shall do his best to give to those... An interesting story with a touch of humor makes the game an amazing adventure. ... A game suitable for all ages, fun and challenging for both hardcore and casual players. ... The game features a broad array of obstacles and challenges.
http://www.southwindsgames.com/site/da/DylosAdventureSetup.exe - 6Mb - Download - Screenshot