While Yooka-Laylee has turned into something of a controversial title, in terms of its critical reception, but one thing everyone seems to agree on (for better or for worse) is that Playtonic's retro 3D platformer does not hold your hand throughout its run time.
That is to say that Yooka-Laylee doesn't clearly sign-post even its most simple aspects, leaving players to flap around for minutes at a time (sometimes longer) figuring it out for themselves. Luckily for you, we already did that, and here's what we found out:
1. Expand Worlds Immediately
Each of the five worlds in Yooka-Laylee can be expanded once you collect enough Pagies. You should make this a top priority, as there's very little reason to womp around in an incomplete world. Expanding a world makes them bigger and unlocks collectibles and even sometimes boss fights.
You can do this for relatively cheap, and, expanding the first world should give you access to enough Pagies to both unlock and expand the next world. Rinse, repeat and you should never have to go into a world without having it expanded.
2. Not Every Boss Fight is Just Lying Around
For 3/5 boss fights in Yooka-Laylee, they will be contained somewhere logical within the level. You can climb to them, or find them in some obscure entryway, but the bosses in worlds 4 and 5 are not found this way.
In world 4 (Captial Cashino), you'll have to beat Kartos' Minecart challenge. Once that happens, the boss will intervene. In world 5 (Galleon Galaxy), you'll have to find the world's MollyCool, turn into a boat and interact with a harmless meteorite. Doing so will anger the nearby moon, who will serve as the boss fight.
3. Hunter is the Best Play Tonic
There are so many Play Tonics (get it) from which to choose, and it's hard to pick the right one on your first playthrough. Undoubtedly, though, it's Hunter. Hunter is unlocked relatively easily, just by collecting two of any combination of Butterly Boosters or Power Extenders.
Once you've unlocked and equipped this Tonic, every special collectible (MollyCools, Play Coins, Butterfly Boosters, and Power Extenders) will give you a suggestive Whistle when you're nearby, even if you can't see them. This is the best way to reveal their location, and getting the Boosters and Extenders are especially helpful as later-game bosses, and especially the final boss, will really tax your Health and Power.
4. How To Use The Flappy Flight Ability
Flappy Flight is the ability that gets you to the final world. Trowzer will teach it to you for free, just off the the right of the path that leads you to the Capital Cashino (world 4). But, this ability is poorly explained, to say the least, and resulted in a disproportionate amount of my overall deaths in Yooka-Laylee.
Trowzer tells you that all you need to do is hold Left Trigger and press X (or Square, for us PS4 controller-users). This appears like a slightly better super-jump and glide ability. But he doesn't tell you the whole story. While you're in the air after initiating the Flappy Flight ability, you can press A (or X on the PS4) to jump while gliding. This will give you another boost. Better yet, you can press jump as many times as you like while in Flappy Flight, bringing you higher and higher, so long as you have the Power to sustain it.
I'm certain this ability will help you out immensely now that you actually know how to use it.
5. You Can't Solve Every Puzzle Immediately
As you may have already figured out, given discussion of abilities, you can't solve each and every puzzle immediately. You'll get to a glass cube and need to reflect light around a corner for example and, if you're like me, you'll spend a good 10-15 minutes trying to find out how, making sure to do a Buddy Slam on every tile in the room just to make sure they aren't hiding anything.
It may be hard to train yourself to do, especially if you're a dedicated collector, but you have to accept that some puzzles you just can't solve until you've unlocked an ability at a later time. The puzzle I mentioned above? You don't unlock the ability to solve that one until after World 3. Do yourself a favor: try to solve a puzzle a few times and move on after that. Don't waste your breath.