And... oh, do you really need me to list them all? See on their site. As a whole, they're compulsive but slight. That they're described as party games nails it. For example, the randomly spawning opposition-slow-down power-up in the froghop game leads to an almost certain win for whoever gets it. It's a bit of a giggle messing around with mates, but not exactly a strong piece of classical game design. Their presence is welcome, but not the main course.
The main course itself is solid enough in many ways. That I'm going to have to reach for fairly abstruse or highly specific reasons why it's rubbing me up the wrong way implies that it gets much of the basics right. My biggest reservation is that it's an arcade game where it's possible to "fail" - as in, make it virtually impossible to win, as in to get the best scores, at least theoretically - relatively early, making the rest of the game pointless. It kind of comes with its dual-world structure. You want to stay in the main world as long as possible to earn as big a bonus as possible. Why make the jump without maximising your score? So you end up regretting your mid-game decision of when to go to death mode, removing the fun from the experience. It feels pointless, whereas Geometry Wars constantly balances on a knife-edge. Biology Battle games aren't too long, but they're long enough to realise that a mass of it is grunt-work.
It also blunts its edge in a few other ways. Most crucial is its toughening up of the opposition. A good chunk of the enemies - even tiny ones - take multiple hits to take down, which makes it feel lumpen. This is mainly to leave room for power-ups to come into play, but the semi-random arrangement of which foes you face at any time means some bits are just plain annoying when you haven't received a necessary weapon upgrade. It also doesn't exactly teach you well - the tutorial is deliberately light, just covering one power-up, shooting and moving, which fails to explain any of the concepts you really need to understand. It also leaves the fancier power-ups - like Blast and Black Hole - a surprise when you reach them. Is six minutes into a fast-paced game really the place where you'd want to experiment? Odds are, the first thing you're going to do upon getting the black hole gun is to kill yourself with it. Your initial emotion upon gaining something you've battled towards for quite a while is "bloody annoyed", which just isn't right.
In other words, it feels off-kilter. There's surface polish, but the more you look, the less deep understanding of the genre is present. Upon starting to play, you get two power-ups on your initial pip-gun to get it up to speed. Why not just start with that if you're only going to have ten seconds going pip-pip-pip? Even the most iconic parts of the presentation - that is, having a mass of short phrases which drop onto the screen whenever you do anything significant - starts to grate, with its choice of phrases making the game appear to be the kid who just quotes whatever is in the comedy-show du jour in lieu of being funny themselves. Its wit is second hand. Space Giraffe, when it took from another source, did so with its own personality. Biology Battle doesn't.
I'm beginning to feel a little like a bully. This is mostly well-executed blasting, and its biggest mistake was to price itself as a direct competitor to Geometry Wars 2. Its design, for better or worse, is its own design. I'd like to see what the developer does next. But until then, I'm back to Geometry Wars 2.