Aeon Must Die! puts the player in the role of an unfortunate nameless Starspawn, a being made of fire. The unlucky hero lives in a world where symbiotic void creatures have embarked on a galaxy-wide journey of extermination, believing that it is their divine duty to extinguish all life in the universe. At the head of this is the evil Emperor Aeon. The game opens up with Aeon betrayed and bound to the Starspawn. As quickly as you can say "Tom Hardy and Venom," the two are forced to work together to survive. Aeon wants to return to the head of his empire, while your character wants to rescue Nebula, a person important to them who is currently being possessed by Aeon's betrayer, Ivory. Naturally, now that the despotic emperor has fallen, every other being in the world is eager to take his head.

Aeon Must Die! is best described as a one-on-one beat-'em-up. It's not a fighting game, and it plays a lot more like Streets of Rage than Street Fighter. Everyone in the game fights you in a one-on-one duel. Defeat one enemy, and another hops in to continue the fight. As the game progresses, enemies on the sidelines might attempt to help out their allies. You can stop this by grabbing and throwing the current enemy at them, which swaps the current foe for another sidelined foe.

Unfortunately, you don't have any allies except for a trust sentient motorcycle. Said motorcycle can't exactly fight, but it can be upgraded with modules, which add a charge mechanic to various buttons. If you charge long enough, the motorcycle is called to do various things. It can prevent an enemy from escaping or swapping out, save you from one lethal blow, throw oil on enemies and more. It makes it feel like things are almost equal.

One of the most interesting elements of the game is how its health mechanic works. You don't have a traditional health bar but a temperature gauge. By default, you're at a nice balanced temperature, but every enemy is color-coded. Red enemies raise your heat when they damage you, while blue enemies lower it. Green enemies push you to whichever extreme you are closest to. If you reach one of the extremes, you go into a special Drain mode for minimum temperature and Overheat for maximum temperature. While in this mode, you need to wait for your temperature to drain, and if an enemy hits you even once, you lose a life.

Temperature is also fuel for various moves. Regular attacks and parries build up heat, while dodges and heavy attacks use it up. There are also special moves that can only be used in Drain or Overheat. Of the two, Drain is more of a punishment mechanic, but you can still make use of it. Overheat lets you spam incredibly powerful moves at the risk of instant death, should you mistime it.

As a result, combat is more of a balancing game. Are you facing a heat-type enemy? It might be worthwhile to dash around to generate a healthy buffer of chilled energy. On the other hand, being in Overheat might let you kill them faster. Depending on the enemy you are fighting, you may feel more comfortable going ham on the foes. As you progress, you unlock moves that give you more options, but they usually have some sort of temperature requirement.

Death is also interesting. Aeon has the power to instantly revive you from the dead, but in doing so, he consumes some of your Purpose, which is what keeps your character from giving in to the evil emperor. When you lose all Purpose, Aeon takes over permanently. You can continue playing as Aeon or go back to your last "echo" checkpoint but lose all progress since then.

Purpose doesn't just disappear, though. When you are defeated by an enemy, they run away and become a Revenge target, and defeating a Revenge target restores any Purpose that you lost to them. They grow stronger with every kill, so that isn't necessarily going to be easy. The exception to this is bosses, who remain where they are, but they'll still gladly take your Purpose every time they kill you. In essence, this means you have a set number of lives that can only be restored by defeating the enemy who beat you.

This is where one of the game's other mechanics comes into play. Enemies aren't just sitting around while you are fighting; they are analyzing how you fight and adjusting accordingly. Most stages build up one of several enemy meters that influence their behaviors. Use the same moves too often, and they'll learn to adapt and be more likely to counter. This ramps up with most fights, including optional skirmishes where you take on Revenge targets to get your Purpose back. If you die too often, even the act of recovering your lives makes the enemies stronger.

The structure of the game is literally a series of arena fights. You'll see a cut scene or two and then are thrown into a fight, followed by more cut scenes. Between fights, you can rest at camp, which allows you to spend Respect points to gain new abilities or to change the modules on your motorcycle. It feels like Slay the Spire but without the randomness. Between missions, you can take on side-quests to earn additional Respect or other prizes, but these come with the risk of death and loss of Purpose.

Aeon Must Die! is a striking game. The art style lies somewhere between Japanese animation and '90s-era comics, and it really stands out. The character animations are strikingly beautiful and make the game's style pop. If nothing else, it's a pure delight to watch in motion, and there are several boss characters that I've only briefly seen, and I look forward to fights to see how they're animated.

Aeon Must Die! may be "just" a beat-'em-up, but it's one of the most interesting I've ever tried. The unusual health mechanic, evolving enemies, and the general style of gameplay help it stand out from the crowd. Assuming the full version of the game is as good as the preview build we played, it has the potential to be a beat-'em-up for the ages. If nothing else, it looks darn good.