There are a multitude of riders to unlock in Kirby Air Riders, so you are almost certain to find one you really like. They will all have different challenges you need to complete to unlock them, some with a couple of different ones available if you prefer one mode in particular. The good news is that there are two different ways to unlock Marx. How to unlock Marx in Kirby Air Riders Marx can be unlocked in Air Ride and Road Trip mode. Air Ride Complete an entire lap of free run without going slower than 30 kilometers per hour. Road Trip Spend a total of 300, 000 Road Miles in the shop The quickest way is undoubtedly through Air Ride, and you will want to combine a rider and a machine that both have a good top speed. King Dedede is a great option here, as the character will be unlocked from the start of the game. During the race, just make sure you never try to boost, as that will slow your speed below 30 in order to get the initial boost going, and you want to do your best to avoid enemy attacks that will slow you. Go into Air Ride, select Free Run, and then Floria Fields. There is only one turn here that might be awkward, as long as you hit the rails and speed boost pads on the ground, but the combination of King Dedede and Warp Star should keep your speed high enough to not dip under 30 even when you hit the far wall. The good news here is that you can leave the mod after you hit the unlock, just hit the + button, and then exit, and you will be good to go. It should be easy to keep a steady speed above 30 for an entire lap, which is actually quite doable with the right driver, as long as you pair them with the best machine you have for the Top Speed stat.
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How to unlock Marx in Kirby Air Riders