Plazmoids!
Plazmoids! is an arcade game for Palm OS that combines superb high resolution, 3D-style graphics, sophisticated visual effects, and addictive techno music and sound. But what makes the game unique is its unusual gameplay based on original physics. We are proud to present this breakthrough game... But since you are not alone in this job, get ready to face numerous enemies, each with their own features and behaviour, master several types of weapon, and upgrade your tiny ship to a powerful space fortress.
http://www.palm-games.com/files/plazmoids.zip - 3Mb - Download - Screenshot

Star Defender II
Star Defender II is a Space Shooter Arcade. It is developed like an advanced clone of old classic Galaga and possesses all the best features of this genre. Again in this fabulous Shoot'em up game you will get a chance to destroy enormous armies of the cruel invaders and to save the Galaxy! ... Your small but manoeuvrable space ship is controlled by your mouse. ... Every new mission has different background witch puts you into the atmosphere of the real Space Battle. ... Each type of enemy has its own model of behavior, weapon and lifetime.
http://www.awem.com/download/StarDefender2Setup.exe - 8Mb - Download - Screenshot

CosmoBlocks
We all love games. That is the fact. Play activity is one of the major parts of human life. Computer is the infinite source of fun and entertainment as it allows making our imagination work for us at its best. Today, fast processors allow creation of extremely realistic game universes while... Enjoy the toughest brick game challenges as you race through space on a fusion powered hyper space ship! ... The game features advanced graphical engine that ensures you actually play bricks aboard of space ship blasting through the myriads of stars and not just dropping pieces into a cup.
http://www.energames.com/download/cosmoblocks.exe - 2Mb - Download - Screenshot

Flatspace
Flatspace is a modern 3D space trading and flight simulation. The ultimate objective in the game is to locate and assemble parts of a galactic hyperdrive, however there is a lot of freedom for the player and as a space captain, you can decide what you want to do and how you want to play. ... To make a profit you could opt to trade cargo between eerie space stations, or become a space pirate and steal cargo. ... As a space captain you can fly any of over a hundred ships in the Flatspace universe, providing you can afford the price tag.
http://www.cornutopia.co.uk/software/flatspacesetup.exe - 16Mb - Download - Screenshot

Flatspace II
Flatspace is a modern 3D space trading and flight simulation. The ultimate objective in the game is to locate and assemble parts of a galactic hyperdrive, however there is a lot of freedom for the player and as a space captain, you can decide what you want to do and how you want to play. ... To make a profit you could opt to trade cargo between eerie space stations, or become a space pirate and steal cargo. ... As a space captain you can fly any of over a hundred ships in the Flatspace universe, providing you can afford the price tag.
http://www.cornutopia.co.uk/software/flatspaceiisetup.exe - 12Mb - 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

Galactic Geometry 3D
Get into the pilot seat and learn about volume and surface area while blasting away space debris to save your ship! Galactic Geometry is a 3D educational game that offers an engaging environment for serious learning about geometric figures. As obstacles hurtle toward them, students must... With five types of rocky debris tumbling through space in vivid animation, plenty of sound and music, three difficulty settings, and relentless brain-racking action (time-freeze capabilities thrown in for the tough parts), Galactic Geometry brings math to your PC in style.
http://www.curryk.com/GalacticGeometry.exe - 2Mb - Download - Screenshot

Storm Angel
The year is 2456 A. D. and Alien elite forces have invaded our space colonies. In a bold offensive move, the intergalactic military defense fleet tried to defeat them but was completely wiped out. Now the alien threat is about to strike planet Earth itself! ... As the STORM ANGEL, the most powerful ship ever designed, is ready to be unleashed on our enemies! ... But a great ship requires a great pilot and it's up to YOU to save the human race! ... - A choice between 10 different weapons! ... - Fight the fiercest bosses ever seen in a game!
http://www.loaded-studio.com/download.php?file=sademo - 8Mb - Download - Screenshot

Starport Galactic Empires
The highly-acclaimed, independently developed MMORPG, Starport, is now available and still 100% free to play. Be the captain of a space-ship in this fully graphical, real-time action game, set in a multi-player world. Fly a spaceship among star systems on a scrolling 2D plane system with... We think you'll enjoy the heart-pounding action of this well-polished space sim, as many other people do! ... Creating a character and getting in the game is very quick and easy. ... Starport is free to play and supports optional donations for virtual items.
http://www.StarportGame.com/StarportGE_240.exe - 16Mb - Download - Screenshot

Netrek
Netrek is a free multiplayer online space battle game. Team up to battle with and against people around the world. As a player, you captain different starships to bomb armies, engage enemy ships and invade planets in order to expand your team's space empire and conquer the universe. ... Think again, since you are always teaming up with different people as well as playing against different people, there is always a challenge. ... Think that sounds easy? ... The ultimate goal being to wipeout the enemy race by battling your enemy with the spacecraft of you choice.
http://www.playnetrek.org/netrek/netrekinstall.exe - 2Mb - Download - Screenshot