Yooka-Laylee World 4 boss INEPT is hidden away as part of Capital Cashino's Extended World.
If you thought World 3 boss Trev the Tenteyecle was tough, you're in for a shock - this is possibly the game's most challenging adversary, and that's not including the mandatory Katros segment required to unlock it.
If you need more help, then consult our Yooka-Laylee guide and walkthrough for finding Pagies and other collectibles.
How to reach the World 4 boss in Capital Cashino
To reach the boss, you first have to play the stage's Kartos level, which can be found in high up at the far right of the stage.
To get there, go straight ahead from where you begin to find an elevated golf course on the back wall. Follow it all the way up until you reach the golf ball at the top. Take the moving platform nearby to the back wall, glide up the gust of air, past the Power Extender, drop down and it's straight ahead.
Alternatively, you can get the stage's Mollycool transformation, and from where you enter the world, turn right and go to the far corner.
As usual, the Kartos challenge isn't easy. It's mostly a case of repeating the level until you remember where all the gems are, but the best tip is outside of the third leap where you need to boost over the large gap, make liberal use of your brake, especially in the air, to avoid bees and missing gold gems on drops or lower levels. Remember you can smash barrels with your projectile too.
As soon as you've completed it, the boss will begin, but if you fail you can skip straight to the boss without doing the Kartos encounter again.
INEPT boss strategy
This is arguably the toughest boss in the game, so don't feel bad if it's causing you some hassle. We'd highly recommended coming in with as many health upgrades as you can, and if you're struggling to take him down, remember that triggering the boss opens the next world anyway so feel free to move on and come back later if you fancy.
The first wave has you leap over waves of bombs, before INEPT dives at you. When he flashes red, wait a half second then fire your cannon, so he'll get hit and retreat before he hits you. If you fire too early, there is a risk it'll sail past him, and firing too late can see him collide into you. Keep practicing to learn the timing.
The real difficulty, however, are the bombs. The first two sets are fairly straight forward being straight apart, but after that they can drop in an irregular order.
Remember to pull back to slow down if the spacing is too tight, and towards the end you'll have two bombs dropping fairly close together close to the end; the best way to handle this is to leap the first three bombs, fire a cannon at the first of these paired bombs, allowing you to leap that cleanly.
That said, sometimes it'll be fourth bombs then a close pair, or not at all, and you won't have time to react to what's coming, and it's this unpredictability that makes this first wave is particularly difficult. We usually work on the assumption it's three bombs, then one pair (which we cannon) and a final single bomb, which saw us through most waves.
Need more help? Our Yooka-Laylee guide and walkthrough explains how the retro-styled platformer works and how to defeat each boss. If you're after collectables, here's where to find all Mollycool locations, Ghost Writer locations, Play Coin locations, Butterfly Booster locations, Power Extender locations and where to find the secret Pirate Treasure locations. Meanwhile, our complete list of quiz answers will help you outsmart Dr Quack.
The second wave is arguably the simplest of all, with the camera moving to a side-on view, and him charging back and forth. When he's on the left and starts flashing, fire your cannon and immediately jump. If you wait any longer, there's a good chance you'll collide. From the right is a little more generous timing-wise, where you can wait until it starts to move before you can leap.
There is a twist, however; after five of these attacks, the sixth will see INEPT stop short before he collides into you. So after firing, wait until he stops, then jump. The same applies on the return trip.
This moves INEPT behind you, firing rockets ahead for you to leap over. Each leap injures INEPT, so the longer you last the more damage he incurs and the sooner the boss will end.
A single rocket is easy enough to leap - as soon as you see it at the screen's edge, press jump - but more is where it gets trickier. The sets of three can be leapt over by pushing forwards to rush after you leap, and the sets of two requires you to time it by pulling back around them.
The bottom line with any of the above waves, and why it's so difficult, is the timing is so hard to judge with any obstacle, so it's highly likely you'll get hit a few times across the way. Practice is key, and again, having some health expansions will help make this frustrating fight a little more survivable.
Additional reporting by Matthew Reynolds.