I know I played against a hacker. He used his special weapon. It had Max blast strenght, 25 projectiles, max damage and land (it was air strike). It killed all my nworms in few turns. Are there some hacking tools and is there a way to prevent these?

No, sadly not. This is not hacking either; this is tweaking the files in the Tweak folder.

yeah is tweaking :) i tell you how to do it go to: program files -->Data-->tweak-->Local

Don't tell. Just don't. We don't need another script kiddie doing lame and unoriginal overpowered crap around here.

yeah, better not...

To prevent in no land use tainail before he/she destroy all land so you can still in the map with no land