The swamp is the second world your ducks come to in Duck Life 4, where they learn swimming. It has three ducks that will want to race your duck(s), two will give you money, and one will give you a tournament ticket, and if you win the tournament, you can move on to the next stage of the game, in the Mountains.
Speed is the first minigame of swimming training. The objective is to go as far as you can. The layout is essentially the same as the first 3 games, as pressing up has you jump, pressing down makes you go down, etc.
Endurance is the second minigame of swimming training. The objective is also to go as far as you can. The training is practically exactly the same as DuckLife 3: Evolution's Professional swimming training (press and hold space to go up, release to go down). It is based off Flappy Bird.
The third mini-game, Timing, is a mixture of "hold it enough, but not too much" and actual timing. It starts off with your duck jumping off the ledge (prompting you to hold space), hitting the water (as close to upside-down as possible), which then sets off 2 circles, prompting you to press space when they touch.