Terrain differences

[brimby]

What is the difference between tar and dirt besides tar always showing up in a circle? Any differences between snow and sand and dirt, or toasted dirt?

[Samail]

Yes. The shape. Which makes them different dirt weapons.

[Zwaken]

No real differences other than looks.

[minmay]

Tar hangs in place after being created, whereas regular dirt always collapses. It's black, so it can blend in perfectly with the background at the top, making it a nightmare on any landscape with very high ground.

Actually, ALL forms of ground - tar, dirt, sand, snow, etc. are the same object, but in different colors. However, the two tar weapons, Tar Ball and Blackout (as well as every other weapon that creates dirt that doesn't fall, like Elevator and Bushwhack) have extra code that makes their dirt hang in place, or every other dirt weapon has extra code making its dirt fall down. The latter is actually more likely; I'll leave you to figure out why.

So, short answer: Differences are purely cosmetic.

[Samail]

Hence
Yes. The shape. Which makes them different dirt weapons.

Good explanation, though.