Let’s get something out of the way: despite its title, Aqua Kitty UDX (which must mean Ultra Deluxe) has very little to do with cats. Cats are the protagonists, sure, but nothing you do is particularly cat-specific. You’re manning (“catting?”) a submarine, defending your feline compatriots from being kidnapped by hostile marine fauna so that they can mine milk from below the ocean floor. Yes, none of this makes sense. If you’ve ever played or are in any way familiar with the 1981 arcade game Defender, that’s about the gist of Aqua Kitty UDX.

This is essentially a horizontal shooter. Enemy fodder consists of cybernetic sea creatures that flood the battlefield in waves. Some of them try to shoot you, others try to catnap the miners. Survive the waves and go on to the next stage (I feel like I just did this). Every fourth stage provides a boss encounter. You only have two methods to deal with the robofauna: shooting an unlimited single shot or a meatier triple shot. You only have so many triple shots, but they are restored over time. Power-ups exist in the form of color-changing drones that, when destroyed, leave behind color-specific enhancements, like more health, drone assistance, or a new shot type.

The whole thing is very ho-hum. Aqua Kitty UDX has a nice difficulty curve, but both Normal Mode (which I just described) and Arcade Mode (which gives you a single life) are kind of rote. Eventually I was just going through the motions, but aside from in-game achievements, I found little reason to keep playing. If online leaderboards are your thing, they may provide some motivation but not for me.

However, a third mode, unique to UDX, salvages the entire game. It’s called Dreadnought Mode. In it, you rescue captured kitties while trying to destroy increasingly complex mechanical monstrosities within a certain amount of time. Each new stage is more devious than the last, and Aqua Kitties UDX is suddenly transformed into a proper bullet-hell shooter. You have to deal with cannons, passing robotic wildlife, and the occasional barrage of torpedoes raining from above. Power-up drones appear more frequently (thank god) but the biggest barrier to success is your health bar. I really enjoy Dreadnought Mode—it puts the other two modes to shame. I will say that its difficulty curve is nearly vertical, though; be prepared to die a lot.

The game has a surprisingly enjoyable soundtrack, too. The spritework is also quite good but everything is way too small. As a result, I recommend playing Aqua Kitty UDX on your TV. There’s also a two-player co-op option, which is nice. In the end, I enjoyed Dreadnought Mode but found Normal/Arcade Mode to be uninspiring. If you need an underwater bullet-hell shooter, Aqua Kitty UDX should scratch that itch.