I actually got asked about Wario World recently. Here's what I replied with:
In my eyes, Wario World is good. It’s not amazing, but it’s good. The reason I say this is because its setup is fantastic, given the engine and tight-ass controls you’re given, the way the objectives are laid out and the puzzles it offers. The thing is about it is that it seems to run out of ideas way too quickly, and that’s not great considering it’s also short.
Despite each level offering some exclusive enemies, for the most part you’ll be battling the same basic enemies all the way through, in about four or five recurring types that are simply reskinned between levels. Gimmicks such as the targets in Wonky Circus, or the reflection tricks in Mirror Mansion are interesting, and should really have been made the focus of the entirety of their respected levels, which would likely have led to consistent a combat environment-centric design.Instead, every so often you’re required to beat up enemies in the same way you’ve already done in prior levels, with the occasional sprinklings of new ones. Despite having plenty of options, it seemed like the best solution for the majority of larger enemies involved the spinning throw, a piledriver, or the choice between either. I seldom had to stop and think about my fighting strategy, put it that way.
The puzzle rooms found in the trap doors are fun to play and work out, especially the outstanding ones such as the final, long-haul Sky puzzle in Pecan Sands. Finding their trap doors and then completing them was very gratifying for me, as was the standard treasure hunting with the buttons and chests. I thought using coins to pay for extra lives was a good idea, but I think the problem was that they were far too generous in how much it costed. Had the price been steeper or gotten considerably worse with every life lost, it would’ve increased the stakes, or (as less original as it might’ve been) Wario Land 4′s system of booting you out of the level without your treasure may have been an option too. A big issue is that I never really felt in danger as I had more than enough coins for extra lives. The game really needed to ramp up the stakes at times.
Cool bosses at the end of each stage is always a plus, and I really enjoyed some of the more memorable ones such as the Dual Dragon and the Mean Emcee. The bosses generally did a pretty good job in varying how you were supposed to fight them, but I must say that doing the aforementioned spin-throws and piledrivers to actually register damage got old fast, and I think should only have been used on a limited number of them to keep things fresh. The Black Jewel at the end was disappointing though, it was far too easy, even by the Wario series‘ standards.
So… All in all, I think Wario World is an alright game, but was in serious need of things to keep players invested, such as better death mechanics and more varied methods to bring the puzzle and combat elements together.