Sonic Month may be over, and the franchise may be settling into its third decade, but my adoration - and coverage - of the franchise will never end. (Let's hope.) With the wealth of material provided to us within these two decades so far, you may very well pretend that Sonic Month is still going on. So, allow me to let you celebrate for real, by giving you the knowledge to beat Sonic the Hedgehog 2 for Game Gear and play it for all it's worth. For this new installment of Sticking Points, I'll turn my focus towards those two aspects which contribute the most to this game's difficulty: the Chaos Emerald locations and the bosses.
Under Ground Zone
Chaos Emerald: In both Acts 1 and 2 of this Zone, there are two parallel paths: an upper and lower path. You start out on the upper path at the beginning of both Acts, but if you fall to the lower level, there aren't any ways to get back up. Your reward for sticking to the top in Act 1 is an extra life item, and in Act 2 the first Chaos Emerald. Note that you'll encounter a mine cart on your way to the Chaos Emerald; to make the final jump, you'll have to bail out in mid-flight.
Boss: *sigh* ...We've hit our first sticking point in the first Zone already. Basically, this boss is a robot pincer which you cannot harm directly, but rather let a series of bouncing metal balls hit it. At least it could qualify it easy on the Wii version, where all the balls bounce low and are easily jumped over. But on the Game Gear, the balls have three patterns: two that bounce high and one that bounces low. and those high-bounce patterns are way tough to dodge. The best advice I can give you is to stand on the kink where the slope deepens, and react to the balls the best you can. Oh, and Robotnik will fly in on his jet-car to deliver the final blow; jump over him and you win. Good luck
Sky High Zone
Chaos Emerald: For the longest time, this was the hardest Chaos Emerald for me to find. Long story short, it's in midair at the top of the level's midpoint. Given the prevalence of hang gliders in Act 2, you would think this is the way to go, but believe me, it's all but impossible to get it this way, however there is a far more reliable, if roundabout, way to get the Emerald.
Along the middle of the entire level is a row of clouds. At some point, you can walk on these clouds. Jump off the right of this "platform" and onto a small cloud with a spring hidden on it. Go right off of this and you should land on another cloud platform. Jump off the left of this platform and try to land on another cloud spring (Hint: it's under the second-to-left column of a cloud). Bounce right off of this and you should hit the second Chaos Emerald.
Boss: You'll start out this fight by facing two waves of small robot enemies. Beat these and you'll fall through the clouds. There are four little yellow nubs which spawn more of these monsters; break these and boss itself will appear: a long-necked bird robot. Hit it anywhere, but avoid the fireballs it shoots, and if you fall behind it, don't let it crush you against the edge of the screen!
Aqua Lake Zone
Chaos Emerald: There are two pipe mazes in Act 2: one at the beginning and one in the middle. In the second pipe maze, just hold Left all the way. This will take you to a small room with the third Chaos Emerald. One of the easiest to find, really.
Boss: A robot seal which inflates and bounces balls on its nose, then attacks you with them. To deal damage, jump on one of these balls when it's blowing one up. Easy, if a little tedious.
Green Hill Zone
Chaos Emerald: In the middle of Act 2, you'll roll down a slope and land on a platform with springs on it, surrounded by a wide field of spikes. Hold Right and land on another platform of springs. After bouncing off of that, hold Right for about... yay, three seconds to land on a high-up platform with the fourth Chaos Emerald.
Boss: The trek to this boss, which involves a lot of springs and spikes, is harder than the boss itself, a sumo-wrestling pig robot. ...Yyyeeeah. This boss will curl up in a ball and move in one of three ways: jumping, directly sideways, or down along the valley in the arena. Jump over or run under the boss depending on how it moves - touching it even while curled up will kill Sonic - and attack it while it's upright. You don't have too much of a window of time to attack it, but just don't try anything daring and you'll do fine.
Gimmick Mountain Zone
Chaos Emerald: Early on in Act 2, you'll go up a slope. At the top, jump to the left and you'll go through a false wall. Follow this path up and over to get the fifth Chaos Emerald.
Boss: A robot pig with retractable spikes on its back. It will charge at you to attack; jump over it and it will hit the wall, causing its spikes to withdraw temporarily and some rocks to fall from the ceiling. Dodge these and hit the boss before its spikes come out again.
Scrambled Egg Zone
Boss/Chaos Emerald: The boss is named Silver Sonic, and I shouldn't have to describe this any further. It uses jumping spin attacks and dashes just like Sonic. Hit it when it's upright, real simple. If you have all five Chaos Emeralds before fighting Silver Sonic, it will give you the sixth Emerald upon its defeat, but if you don't, the game will end when you beat it, and you won't be able to experience the...
Crystal Egg Zone
Boss: Yup, it's Robotnik time. You fight him in a small room looped by a pipe. Robotnik's attacks include flower-shaped bullets that spiral out from the center of the room, lightning bolts that travel along the floor, and an electric flash which engulfs the entire room. Fortunately, you're invincible when traveling along the pipes, so just be patient and you can win and rescue Tails.