You will have a variety of trophies and achievements to unlock in Like A Dragon Gaiden. One such digital trinket is called Whip-Splash, where you must throw an enemy into the river with the Spider gadget. This is fairly easy, although the game can be a bit finicky, due to how the Spider gadget works.
How to Unlock the Whip-Splash Trophy/Achievement
Before doing anything, you will need to unlock the Spider gadget, which is actually pretty easy. This is the first gadget you will have access to in the game, with it being there from the very beginning. In order to use this gadget, you will need to make sure you’re in Agent style, as Joryu cannot use it in Yakuza style. With that out of the way, once you’re in combat, you just hold down the Circle/B button to unleash your wire. If you keep holding it down, you can move your left analog stick in a direction to fling that enemy, with the impact causing some damage.
As mentioned in the opening paragraph, your goal to unlocking this trophy/achievement is to throw an enemy into the river. The river is located in the middle of the map, between the Bishamon Bridge and Iwao Bridge. It is best to go on the Sotenbori Footpath on the southern side, or the one on the northern side of the river for this. This seems to give you a lot more room in trying to toss an enemy, over the bridges themselves. Of course, you’re going to need some enemies, so you’ll likely going to be going from one end to the other looking for them.
Once you have triggered a fight (the random enemy encounters are best, simply because of the ease of the foes you face), it’s time to get started on this trophy/achievement. While you can fling enemies in any direction and hope for the best, it’s easier to do it when you throw them straight over your head. That means you will want to have your back to the river and the enemy directly across from you. Note that if you have the Spider gadget upgraded under your abilities tab, then Kiryu will throw out more wires when using the gadget.
That’s about the only problem with this trophy/achievement, since positioning is a big thing here. There doesn’t seem to be a way to toss them into the river when doing it to the sides, as the enemies don’t get enough height to clear the railing. As soon as you manage to launch an enemy into the river with the Spider gadget, you will unlock the trophy/achievement.