Video game crossovers have fared a lot better than those in the worlds of film and television, but when it emerged that plans were brewing to bring together the worlds of Nintendo icon Mario and Ubisoft's mischievous Rabbids, very few people expected it to work.
Leaks and rumours made it clear such a game was in the works, but when it was finally revealed officially what took many by surprise was that it would be a strategy RPG in the vein of Fire Emblem and XCOM.
Revealed at E3 with the memorable image of Mario creator Shigeru Miyamoto and Ubisoft CEO Yves Guillemot brandishing huge toy guns at a crowd of journalists, this unlikely game ended up being one of the most impressive of the show.
In inter-dimensional set-up brings together the two worlds, and it's every bit as silly as you'd expect. It's not long before Mario is teaming up with Rabbid versions of his friends in a warped version of the Mushroom Kingdom overridden by corrupted, hybrid Rabbids.
Your team, led by Mario, starts out with the wonderful, selfie-loving Rabbid Peach and Rabbid Luigi, with new members added as players move through each stage of each world (1-1, 1-2 etc) in a space that plays out like a gorgeously realised version of the overworlds from classic Mario platformers.
Battles are marked by flags and an obvious change in play, but each battle's staging area is part of the overworld's design rather than another abstract plane, giving the game a nice coherence as it jumps between its two primary forms of play.
Between battles you'll move from point A to point B with bonuses to root out through light exploration and simple puzzles. Some involve pushing blocks, moving statues, collecting coins, but the tougher they get the more apparent it becomes that the loose movement isn't well-suited to puzzles requiring precision and timing.
Of course, all this is in the periphery. The core of Kingdom Battle is its turn-based strategic combat, which surprises with its depth and complexity and quickly shrugs off the 'XCOM for kids' moniker presumptive critics gave it.
Each character can use a weapon, an ability and move each turn, unless that is, the character has been impeded by an effect which limits one of those actions. Between the teams of three these can moves be enacted in any order the player wishes, creating a wealth of potential mix-and-match strategies to consider.
A neat quirk allows characters to increase the range of their movement by boosting off an ally, with later abilities introducing certain boosts where particular characters land. Each hero can also chip away at an enemy's health by sliding into them while moving to their next piece of cover.
That's a lot to consider even before the environment threats, the topography of each arena and the wealth of enemies between you and victory. These warped Rabbids can vary from powerful, melee-minded goons that immediately chase down whoever attacks them to ghostly Rabbids that travel quickly over each arena and health-dispensing foes with pockets full of grenades.
Outside of battle there are also a lot of weapons and abilities to be upgraded and unlocked. In a nice touch, a character's skill tree can be reset to zero at any point, allowing players to spend experience again to tailor what they can do for certain tasks ahead.
Mario + Rabbids is a surprisingly rich strategy game that also presents a significant challenge. At times it's even unforgiving.
Chapters can consist of multiple battles strung together, with only a slither of health offered back between bouts. Couple this with enemies that aren't averse to hammering you into submission and players may often find themselves approaching a second or third battle with not enough health to see it through.
It's not unfair, but the game wouldn't have lost anything if it did heal characters between successive battles. As it is however, there are points where the game puts you in a losing position immediately after a big win, before the next battle has even started.
There's an easy option available before each battle gets underway however, which boosts each squad member's health. Later on in the game, however, even this presents players with a firm challenge to overcome.
Mastery and understanding of the strategies available at any given time is crucial to beating the game, and Kingdom Battle doesn't exactly ease you into that mindset. It quickly becomes apparent though that players need to consider team interplay and makeup to excel.
Nothing about Mario Rabbids should work. It's enough of a shock that Ubisoft Milan managed to bring together these two worlds so well, then it successfully makes its cast the stars of a genre none of them has ever been near. Robust in how it plays and confident in its presentation, Kingdom Battle is exactly the kind of bold and fun exclusive Switch needed in its first year.