Luck-Based, but Good
Instead of the Graphics/Sound/Violence/Humor/Style/I nteractivity scale, I'm going to rate each phase of the bosses. We know the drill; the engine is the same for all of the games, even if the gameplay isn't, the graphics are done by Luis, so they're just great anyway, the animation likewise. We know BoMToons' reputation. So let's cut the crap and review the gameplay:
BOMBS: This is the first, and easiest stage. It's kind of weird having a non-boss battle sequence when the rest of the game is, though. It's somewhat out of context. Additionally, it's very much luck-based, like some kind of die roll when you start the game. On one occasion, I got a spreader, bombs, another spreader, and an extra life before I even faced the boss. On another occasion, I got nothing.
ARMS: The way the arms act independently can be kind of annoying. It's nearly impossible to act preemptively before an attack can hit you, such as double laser lacerations, or a laser ball with the rocket lasers. It's kind of luck-based just like the roll. Especially with the bombs that pop out. I got missiles and a spreader just after entering the battle, and as a result I won the whole game without losing one life. Again, very luck based.
UFO: Thankfully, this is a bit more of a skill challenge, as the UFO follows a bit more of a distinct pattern. Run between the lasers, dodge the beams, shoot the minions, etc. However, it annoyed me that the best way to avoid the lasers was to spam Down + S, not because it was too easy, but because it was such an unnatural notion for such a physics-based game. It was also annoying that the gun knocked the minions back so much; you couldn't tell if you had gotten them all or if one of them was gonna flank you from behind.
SQUID: This was really fun, as it's a falling sequence. There's a cool avoiding sequence, and it's a welcome change. Unfortunately, I was a bit irked that when the squid summoned rockets, if you were in the wrong place, you got zapped instantly. Once again it was kind of luck-based. I'm not saying skill isn't involved, but I'm saying that luck does warp the gameplay much more than it should.
BRAIN: The most damaging yet weakest phase of the boss battle. It's kind of neat to compensate offense for defense when you have a time limit. Although it was kind of annoying getting constantly zapped with little to no patterns, it was a little fun.
OVERALL: On a normal game, I could get to the brain battle, but the game is so luck based that when I got triple missiles, I was able to beat the brain in 30 seconds. I'm not complaining that I won, but I am a bit upset that your games are not only ridiculously similar, but also have so much luck. I'm sure this review has gotten redundant, but nonetheless I find it important to state the facts. Still, a good game, but 1 point off because of balance issues.