Atomaders
This space-shooter is based upon the classical Invaders/Galaxian idea. You have to liberate your planet system from the alien invasion using your spacefighter. Player can obtain various extra-weapons and special abilities by destroying enemy cyborgs, fighters and motherships. ... Additional planet systems could be downloaded from the Internet. ... Each planet has its own cyborg types and an unique powerful boss at the last level.
http://kraisoft.com/files/atomadersdemo.exe - 9Mb - 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... The icons, of course, have been augmented with powerful weapons of their own, and it will be very challenging to defeat them all. ... Only you can stop the icon invaders. ... Requires DirectX 9. ... 0.
http://www.sb-software.com/wheniconsattack/sbicon11.exe - 3Mb - Download - Screenshot

Political Invaders
Your mission, should you choose to accept it, is to plaster as many politicians and their henchmen with pies as you can. The politicians, who don't really like getting blasted in the face with a pie, will drop bombs on you. The bombs will do you great bodily harm, so you would be wise to avoid... The game plays similarly to "Space Invaders" with a touch of galaxian or galaga, and with some fun and unique twists. ... Please don't take offense if we make fun of your particular political heroes. ... In addition to american politicians, you can also choose to pie world leaders if you desire.
http://www.sb-software.com/politicalinvaders/sbpol14.exe - 3Mb - Download - Screenshot