The shield doesn't reliably stop any projectiles whose velocity is more than 1 cell/tick, and doesn't stop anything that doesn't use or subclass Projectile. Glittertech projectiles are probably just too fast, so would require a specific patch on the glittertech side to work.

does that mean that it doesn't block sniper bullets?

So the way it works is, every tick, it scans the cells on its perimeter for projectiles. This means the projectile has to be in one of those cells at least once. I'm not sure what velocity the sniper bullets fly (I run CE), but you can estimate the odds of a projectile penetrating as 1-(1/speed). Also, if the projectile isn't coming straight in, it has to go farther than 1 cell (1 cell diagonal), which decreases the penetration chance.

Ok thanks!

Awesome! Thank you for the reply, now it makes sense. Very interesting as well, I had no Idea it worked like that