Donkey Kong Country Returns has a similar history to Hyrule Warriors when it comes to its three different releases. It first came out on a console, the Wii in this case, and then later received a port on the Nintendo 3DS. That port made things easier on you and also offered new exclusive contents, but it it looked worse and halved the frame rate to get the game even running on the smaller system. Some years later you get the "definitive edition" on the Nintendo Switch, which offers the improvements of the Nintendo 3DS version without the downsides in the graphical department. And that's very nice to have, but are there really no compromises...?
The port was done by Forever Entertainment, a fairly unknown Polish studio, where this is their first time working for Nintendo. It was completely rebuilt in Unity according to Digital Foundry, where – for a Unity game – the performance is impressive overall, but it doesn't run as smoothly as Tropical Freeze does. You will encounter dips in the frame rate here and there, which you may not even notice, but they are there. This is still much, much smoother and playable than the 3DS version was, but it's not quite on the level of the Wii version.
And there is one major downside over both its previous versions: the long loading times, which even exceed those in Tropical Freeze. When playing the game normally this isn't a big deal, but it completely breaks the Time Attack mode, where they haven't bothered with fixing its main flaw. If you die, it will put you at the latest checkpoint with the timer still running, which is about as useful as the rewind feature in Nintendo World Championships: NES Edition, meaning that it's completely pointless whenever you're going for the best times. And if you chose "Retry", it will load the entire level again, which is where the loading times will make this very tedious. Too tedious. This is something that they already had overhauled with Tropical Freeze and this would have been a much needed improvement for Returns HD as well.
Overall, it seems like the port was based on the Nintendo 3DS version, which means that it comes with all of its improvements, but also with most of its flaws. It certainly looks better and has a much higher frame rate and resolution. You also have better control options, where the left analogue stick and the D-pad are active all the time and you can switch between them whenever you want, as you would expect with such a game. But there are some rough edges otherwise.
For example, the final boss still doesn't drop a shadow, which was a critical indicator for landing the last hit without being hit, making this boss fight very frustrating in Mirror Mode. Most of the enemies got their shadows back on the Switch version, though, so this feels like an oversight.
And the Super Guide pig still shows up everywhere whenever you die eight times in a level, even in the very challenging temples, which is just annoying. They should have given you the option to turn it off completely. Or at least hide the Super Guide in Classic Mode, because whoever plays in Classic Mode obviously doesn't want any help. At least the game never punishes you in any way when the Super Guide has appeared, unlike New Super Mario Bros. Wii and alike... (And it never did.)
Speaking of Classic Mode, the Nintendo Switch also comes with what's now called "Modern Mode" and works exactly like the "Normal Mode" in the Nintendo 3DS edition. So, you get one additional heart per Kong and there are other helpful items found in Cranky Kong's shop, where the inventory space was even increased now. Switching between the modes is not possible.
If you want to play Returns in it's coop mode, however, then you will face one of the biggest issues from the Nintendo 3DS version: there are no lingering bounce "boxes" left by enemies any longer. On the Wii it was possible that both players can jump off the same enemy with the correct timing, because there is still something to bounce off from after an enemy gets defeated, for a couple of milliseconds. This was missing on the Nintendo 3DS and now it's missing on the Nintendo Switch as well, making some of the harder levels nearly impossible to play cooperatively.
There are also some general issues with the game that never were fixed in either iteration, like how you can't repeat puzzle rooms without killing yourself. And the collision detection with enemies and obstacles feels overly tight, where it could be more forgiving. But that's all debatable, so there might be no need to change anything here. And some aspects are general design flaws with the game that cannot be easily fixed, like the blowing mechanic, which wasn't brought back for the sequel.
Anyway, with all this said, it's still the best version of the game and this is very nice to have on the Nintendo Switch, right next to its younger sibling, Donkey Kong Country: Tropical Freeze. Being able to play both games back-to-back on the same console in 1080p and (mostly) 60FPS is a treat. And this also allows you to play the eight additional levels from the 3DS in HD for the first time, which is lovely and makes some of them shine a bit more.
Whether this justifies the full price point or not is a different question, however. In the face of Metroid Prime Remastered, which is one of the best-looking games on the system, while costing only 40€, this doesn't make any sense. Both of these were games by Retro Studios from the GameCube and Wii era, and their Nintendo Switch remasters were treated very differently for some reason. But in the overall picture of Nintendo, it's really Metroid Prime Remastered that is the outlier here, while Donkey Kong Country Returns HD is simply more of the usual.
Speaking of the usual Nintendo issues, the credits read again "based on the work of the original development staff", which means that they are completely skipping over the cast from both Retro Studios and Monster Games. This is not okay and never will be okay. Forever Entertainment is not the creative mind behind Donkey Kong Country Returns or any of its contents, but the credits make it look that way.
Anyway, if you're a fan of the game and want to replay it in its best version, then you can't do much wrong here. And if you haven't played it yet, it's highly recommended to give it a try, because Donkey Kong Country Returns is a fantastic platformer all in all. Just keep in mind that Tropical Freeze is the better game for the most part. So, maybe wait for a discount.