I finally got around to downloading Worms Rumble for PS4 yesterday. I'd have to say that this turned out to be a very good game!
I got slaughtered rather hard on my first few games. My game has steadily improved after becoming more familiar with the weapons and the level layouts.
If you're just starting off, I recommend that you take some time to learn about the various weapons. Learn their attributes, figure out which weapons are best for particular situations, and how to acquire and switch between them in the heat of battle. The game includes a training area where you can practice with the weapons, but you should also put in a few actual game sessions to see how they affect your opponents.
It's also worth learning the playfields and how to navigate through them. There are some opportunities to conceal yourself and hide from opponents, so that you can prepare to deliver a surprise ambush!