Do You Think Nexon Will Nerf The Island?

The only thing that may need a slight consideration is the pinboom in the darkroom after entering the hatch. They give about 400k exp per kill.

But they're not really bunched tight together and the invisible platforms make it quite hard to kill efficiently. A BW, Luminous or DS might say otherwise though.

Actually sometimes they replicate almost instantly. Also moving around is pretty easy, at least if you have an easy jumping class like the Cygnus Knights. Xenon can fly but it's pretty slow/cumbersome so they're pretty limited, as are classes that don't have easy/strong vertical jumping capability. They have a LOT of HP though. You probably need to be at like 500k range to be able to one-shot them. I think it takes me like 2 or 3 hits at 300k (unbuffed). An over powered Luminous probably has the best advantage overall... although that kind of goes without saying.

So far the best/easiest form I've found is refixing the broken mounts over and over again. I've gotten pretty lucky though amassing a horde of screws and animal oil from n00bs who don't know any better. I usually offer them a few hundred thousand for whatever they've got on them. Some people might find that form a bit hard though because you have to be able to do simple math VERY quickly in order to get the best use out of it. The purple fuel and control boards are simple because it just used one at a time and likewise screws are pretty easy because they're in sets of ten, but the animal oil is in sets of 30, so if you can't quickly do the substraction in your head on the fly it may be a bit difficult for some.

Also, for some mules there's this glitch where if you go into the same portal it just takes you back to the previous map. And if you transverse from one side, back in, then back to the other, then you'll get a new map. So as long as it's not the main beach map you can keep doing it until you get the perfect combination of ancient robot and white rhino, then just clock back and forth until one of them gets raptors (you'll need to eliminate any robots, centipedes, mosquitoes and researchers that pop up to make it cycle). That method works almost as well as repeat mount repairing, but I've only had that one particular glitch pop up on one mule so far, so I don't know how common it is.

Again though, most of these tricks are for "regular players". If you have a range that clocks into 500k or higher then you can likely get more out of one-shotting ancient golems or in the drill halls. For "regular players" getting to level 210 is at least in the realm of possibility and level 220 to 225 is a good long term, multi-year goal... but unless your range is over 500k and you want to devote countless hours to grinding... yeah, getting over 225 is basically an impossibility.