NIS is a publisher known primarily for quirky, Strategy RPGs, which makes Puchi Puchi Virus, a puzzle game, a bit of an anomaly. While the genre might be different, Puchi Puchi Virus does retain the amount of random quirk the company is known for. The entire game is presented in a hyper-active anime style, complete with odd-looking monsters and big, bright characters with even bigger reactions to everything.

Presentation is split between two screens. Gameplay takes place on the bottom screen which is populated mostly be small, squirming multi-colored viruses. Although small, it is easy to tell the difference between the viruses. The top screen plays home to your two assistants, a human nurse and a giant chicken nurse. As you clear out viruses, the two run around the top of the screen in a panicked state. It's a fun distraction that helps set up the game's narrative identity, though it is also something you aren't likely to ever notice for longer than a few seconds at a time. Your only real clue about what is happening on the top screen are the sound effects that are constantly playing in the background. While helpful, the sounds aren't so distracting that they can't be tuned out.

A virus, called the Puchirus, has infected the entire town causing people to turn into animals and other odd-looking monsters. You play the part of a doctor who has discovered a way to cure people using the power of pure awesomeness. Part of the cure involves isolating like-colored viruses and destroying them by linking them together in groups of three.

Gameplay is incredible straightforward and doesn't really throw out too many curves. The single-player game is broken into a number of levels, each represented by a patient. Some levels require that you earn a set score in a short amount of time (usually no more than a few minutes), while in others, you need to create a certain number of chains. Of the two, the levels that require you to create chains are the more challenging and entertaining, mostly because of a pretty big exploit (detailed in the next section) that torpedoes most of the score-based levels.

Other than unlocking new, more challenging sets of patients, there isn't a whole lot to the game. Hardcore players who have no problem sinking hours into puzzle games will find much more to like than the more casual sort. Even with stricter time limits and the introduction of more virus colors, the gameplay can become a little repetitive and unrewarding beyond the intrinsic ones that come with beating a level. It's probably too much to ask for any more from a puzzle game, but at the same time, a little more content (different modes perhaps) wouldn't hurt the game's longevity. On the plus side, Puchi Puchi Virus includes a single-cart multiplayer variant, which adds a little something to the value.

Mastering Puchi Puchi Virus is more about dexterity and awareness than anything else. There isn't a lot of time to think out moves and though you aren't punished for bad decisions, they can complicate things. Thankfully the mechanics are incredibly simple, though this also opens the door for a major exploit, at least when it comes to the score attack levels.

The play area on the bottom screen is very small and viruses tend to populate the play area really quickly, causing them to bunch up. Since there are so many viruses bunched up close together, it is possible to quickly clear out viruses just by rapidly and randomly tapping the screen. It was a technique that was born from desperation, but one that works incredibly well in most instances. Seeing as how it removes thought out of the equation, it won't help you to win every level, but it works well enough that you'll get through most of the game without much trouble.

All of the action takes place on the bottom screen. In order to destroy viruses, you need to touch three viruses, creating a transparent triangle on the play field. Tapping one of the three viruses in the triangle destroys the viruses. Although it may sound easy, the triangle must be formed and deleted quickly, otherwise the viruses crystallize and are rendered useless. However, you can revitalize crystallized viruses by either trapping them within a triangle or destroying it, or by using a pill.

Before destroying the triangle, you can also try and form additional triangles by using active viruses trapped inside the original triangle. In other words, if a green triangle is created, all viruses in the triangle are also activated. If two blue viruses are trapped and activated, touching another blue virus will create another triangle that is linked to the original. Destroying any of these groups will destroy all of them, earning you more points. The downside is that if you can't destroy the groups, all active viruses become useless.

The concept behind Puchi Puchi Virus is a solid one. The mechanics are easy to learn and the game is fun. However, the random tapping loophole does take some of the fun out of the game and indicates a few loose ends in regards to how the gameplay plays out. Still, if you're a puzzle fan and not one to fall back on cheap techniques, Puchi Puchi Virus is worth a look.