A brief tour of Kelp Dome, using mission 8 of the single player as a preview.
Similar to Saltspray Rig, your base isn't enterable by the enemy. The walls surrounding it at ground level are not climbable due to a lip at the top. Unlike Saltspray, the area is quite small, and a single inkstrike will be able to hit most of it. There's an exit ramp leading out to the left, and a higher perch for sniping/base defense.
Leading out of your base to the right are two ramps. The first gets you up to the catwalk, and the second gets you into a room directly across from the enemy base. There's no way back up this second ramp from the other side. Consider standing at the top and raining ink down into enemy territory. Also, remember that your enemies may be doing the same thing to the left of YOUR base. Consider tossing bombs onto the ramp from below, or a sprinkler.
To the left of your base is a close ramp leading up to the catwalks, and at the far left is a small square room, the one mentioned above that can be entered using the second ramp to the right of the enemy base. This room has a short wall that can be used as another entrance to the catwalks, one of few walls that can be painted on this map.
Don't forget about this little dead end left of base. This is one of very few paths the enemy can take toward your base; they could even use it to circle around into the center and get behind you and your teammates.
Also taking a left out of your base, ignoring the catwalks, you can then turn right to enter a tunnel leading toward the contested center room. The catwalks will often be quite dangerous to take, so consider this route to the center, even hiding down here and watching for enemies arriving from the center room or on the catwalks above.
All roads lead here. Expect a lot of action. The structure in the middle can be painted and climbed.
Overall, Kelp Dome is a small, claustrophobic, and likely very violent map.