The first time I heard about Mario + Rabbids Kingdom Battle, I was hunkered in my hotel room in Los Angeles during the E3 expo in June. I was feverishly preparing a presentation of my own game, XCOM 2: War of the Chosen, while half-listening to the Nintendo press conference in the background. I didn’t pay much attention. It seemed a vague stream of soothing words like “amiibo” and “Yoshi.”

And then I began to hear something else: familiar phrases, to me at least, like “turn-based tactics” and “half cover.” I paused, turned up the volume, and watched.

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It was one of the most surreal experiences of my professional life. There was Luigi, sliding into cover, his gun at the ready. There was Mario, unloading a volley of blaster fire from his overwatch position. And there was Princess Peach, weighing a 50 percent shot on an enemy.

My phone began to ding. A steady stream of text messages, emails and notifications from friends, colleagues and journalists that boiled down to one question: “Dude, did they put Mario in an XCOM game?” Mario + Rabbids Kingdom Battle turned out to be much more than that. And after that immediate sense of shock when I saw the game for the first time, my next emotion wasn’t fear of competition. It was hope.

The nice thing about working in a genre like turn-based tactics is that it isn’t a zero-sum game. Good tactics games create new tactics players, and then everyone in the genre benefits. Besides, the game looked beautiful and fun, and I wanted it to be good because I wanted to play it. Not even two months later, we all found out that Mario + Rabbids Kingdom Battle really is beautiful and fun, and it is very good.

It was one of the most surreal experiences of my professional life

Make no mistake, it isn’t XCOM. There is cover, yes, and flanking, and a few other elements that look familiar. But the missions play out in completely different ways. In XCOM, we script as little as possible. We design complex systems like AI, procedural environments, mission objectives and soldier abilities, and then we just sit back and let those systems play out. We have no way of knowing when a player is going to confront a particular mission, what enemies will be there or what the map will actually look like. Even as the designer, when I play through a mission I’m constantly surprised. There is no “right” way to play XCOM. If you survived the mission, then no matter how you did it, you did it right.

In Mario + Rabbids Kingdom Battle, there is very much a “right” way to do things. The missions are hand-designed, and they are essentially puzzles that the player must solve. In XCOM, player stress comes from the understanding that the game does not care whether you win or lose. The game is simply an unfeeling collection of systems. Your favorite soldier was just killed? XCOM doesn’t care. The rules are the rules, and when you make mistakes, there must be consequences.

In Kingdom Battle, the stress comes from knowing there is only a narrow band of choices that will lead to victory. Every choice you make could set you down the wrong path, and in later missions, the band of choices narrows even further. Yet the stress of combat is also offset by powerful new innovations to the tactics genre. Movement is surprisingly fun and kinetic, with allies leaping off of each other, sliding through nearby enemies or traveling through pipes to completely different areas of the battlefield.

Good tactics games create new tactics players, and then everyone in the genre benefits

Who knew that a game put together from such disparate parts could make such a satisfying whole? Mario leading a squad into turn-based combat against the Rabbids, combined with a puzzle-heavy real-time overworld exploration game? It sounds like an idea hastily scrawled in a junior-high notebook.

Playing Mario + Rabbids: Kingdom Battle, I had many moments where I laughed out loud, or felt a twinge of jealousy at a particularly clever mechanic, or felt that most coveted gaming moment: the exhilaration of a worthy challenge finally overcome. All of this happened in a game in a genre I supposedly know as intimately as anyone can.

Mario + Rabbids reminded me of how much I still have to learn as a designer. Making XCOM is very rewarding. It is also excruciating. Every version is a yearslong process fraught with stress, doubt and long, long hours. When it’s that hard to do something well, you can convince yourself that you must be doing it right. Innovating on core concepts seems not only risky, but wrong somehow. As a designer, your vision narrows, and any challenges to your core design pillars sound like heresy.

What a joy, then, to have another team come along and upend your thinking, showing you that there is always room to improve on old concepts. For example, in XCOM, moving a soldier is typically a simple case of running them from cover A to cover B. That’s how it’s always been, and it’s not something I ever thought of changing. Until I played Mario + Rabbids, that is, where movement is a chain of interesting decisions like springboarding off of your squadmates, sliding through your enemies, rolling through warp tunnels — all before you fire a single shot. Movement in Kingdom Battle adds a whole new layer of tactical interest to every turn. It jolted me into reconsidering one of XCOM’s design principles.

Not that anyone should expect bright colors, talking plants and crazed forest creatures in the next XCOM. But don’t be surprised to see movement work completely differently. This, ultimately, is the delight of Mario + Rabbids: Kingdom Battle for me: to have a worthy competitor, or perhaps a worthy compatriot. When people make good games, everyone wins.