To defeat Dr. Cranken easily, use Sylvia. It is possible to defeat him in the first part with Joe, but it is much easier to use Sylvia for the entire battle. Cranken has three main attacks. He will sprout three tentacle things from his back, and they will have one of three things on them: drills, magnets, or buzz-saws. They will also appear in that order. Drills will stab at you, magnets will pull drills from the ceiling to fall on you, and buzz-saws sweep across the floor and up in the air to hit you. On one of the tentacles will be a yellow ball. This is your target. Go Slow Mo and shoot it with Sylvia (or punch with Joe). After four hits, the tentacles and Cranken's shield will break. Use this chance to run up with Sylvia, go Slow Mo, then activate Replay, Zoom In, and Spin Kick all at once. You can get about three of those in. Repeat this quite a few times. When he gets to two life bars, he starts to glow red. He will use his magnets to pull down about four of the six pieces of ceiling, raises a column forcing you jump over it, and makes avoiding the ceiling difficult. He will also call out three of the flying probes. After a few of those, he will pull out a drill/buzz-saw mix. Repeat what was doenbefore and hit the ball. After you take out his life bar, his body will explode and you will fight his head. You will have to use Sylvia for this. He will be shooting drills, and balls with be around his head. Hit the one that is glowing. Once you hit it, it will start moving around his head. Use Slow Mo and shoot. When his shield disappears, do your Slow/Zoom/Replay/Kick. Keep pressing Kick and you will kill him easily, because his defense is nothing in that form.