After the first try to penetrate the shield, Serious Sam entered Sirius, but unfortunately, Alliance forces were unable to pass through it, due to the Kronor Cannon losing power...so those forces were literally fried like ducks...
Serious Sam tried disabling the Shield Generator but he was lured into a trap. Sirians set up a classic trap, involing a Banana and a rope. Afterwards, after competing in some games, Serious Sam was rescued by Alliance forces that penetrated it themselves (probably using the Kronor Cannon) and fought along his side...but eventually were brought down by Mental's AA weaponry..
- The Sirian Shield seems to be completely offline after the Mental Institution was destroyed, or Mental's minions disabled it to allow him to escape from death.
- The Sirian Shield looks similar to the Invulnerability Power-Up in the game...in a different color...