I didn't find out yet how to tweak this game. Has Team17 disabled that kind of feature, or am I doing something wrong?

Thanks in advance,
Tarek701.

Yeah, they've been completely disabled now.

I don't think so. I've seen a tweak with two hats that haven't seen in the previous worms games before. I will post the link here when I find it.

Happy Worming!

EDIT: I see that you meant tweaking like you could do in Worms 4, but here is the link anyway http://www.worms4tweaks.com/t301-ultimate-mayhem-hats

Yeah, they've been completely disabled now.
No, doesn't seem to be true. Just found out, that XOM Viewer + Edit allows you to edit the stuff via Hex Edit. Just tried it myself. It's not that easy anymore, like opening notepad with WeapTwk.xml. But still I was able to change damage, radius, etc. So, it still works, just in another way. XOM is a kind of compiled XML file. But still the algorithm is simple.