Super Lucky's Tale is a fairly simple 3D puzzle platformer. You goal: to defeat the cat-themed gang that's trying to steal the Book of Ages, restore peace to the people within said Book, and return to your sister.
In the base game, there are 4 hub worlds to traverse. A certain number of 4-Leaf Clovers are required to fight the boss of each hub world, and luckily, there are four of them in each level of the hub worlds. There are also a number of puzzles to complete in some of the hub worlds, which will give you extras. There are a total of 99 Clovers in the main game (18 more via DLC for a total of 117).
Mechanics-wise, this game is pretty solid. You jump and double-jump your way over obstacles (and jump on enemy heads, Mario-style). You also can dig underground in a lot of places, adding an additional wrinkle to some of the puzzles. You have limited control over the camera, with three predefined angles to work with. Most of the time, it's a pretty decent setup. The controls are reasonably smooth, too.
Most levels, you can 100% in a single run without too much trouble. Simply collect 300 coins, all five letters of Lucky's name, complete a puzzle, and beat the level and you'll end up with 4 Clovers. There are a few that are a little trickier (more limited coins, hard-to-see optional switches, etc), but overall it's very doable.
The title updates are a pretty blatant grab at trying to extend the time playing the game without adding more levels. It basically boils down to collecting coins and buying costumes. Not my cup of tea, but I suppose you do need something to spend those coins on.
I thoroughly enjoyed the Gilly Island DLC - I feel it would have fit in nicely with the rest of the game, with fun levels and puzzles. The final boss was a bit harder than the rest, but it's still well worth it.
The Guardian Trials DLC was pretty challenging. No real "levels", but it does provide a number of puzzles, platforming challenges and a couple of remixed boss fights. For those who finished the base game and want a little more kick, this is for you.
All said and told, this is a pretty fun game if you like Mario-esque 3D Platformers. It's not a long story, or a deep one, but the gameplay's enough to enjoy it well enough.