Erika got it!

1. Attack of the clones!

Mephiles clones all around

2. WORTHLESS CONSUMER MODELS

Omega is playable in some parts

3. Purple floor?

The floor will turn purple

NEXT POSTER GETS MY TURN BECAUSE I´M LAZY. :DDDDD

DO IT YOU LAZY BUM

Wait, so who has it now?

Oh, shi-

NEXT POSTER GETS MY TURN BECAUSE I´M LAZY. :DDDDD

I'll bite!

1) Haven't we met before?

2) Boing boing

3) Birds in a water level?

Sphere-O-Bot, Aqua Planet Zone, Sonic Chaos?

Darn. Knew I made it too easy.

1)  The little bird bots are reminiscent of the ones from Sky High Zone of Sonic 2 8-bit
2)  The boss bounces
3)  Again the birds

Your go.

1. A series of tubes
2. Those little lights are practically begging for my attention
3. Bullets, fire, and now outright chaos theory

Final Boss, Sonic 2 Game Gear version?

Not today, Zurg.

Damn. (Btw, is that first clue referencing Ted Stevens? "And again the internet is not something you can just dump something on. It-it's a series of tubes!" )

Mad Matrix boss, Shadow The Hedgehog.

Again try.

Can you give us another clue, Rappy? At this rate it's going to end up vanishing into the depths of page 2 again.

Very well.

4. However poor your perspective is, don't panic: after this is the final fight.

Panic Puppet Zone boss, Sonic 3D!

Indeed it is.

1. Robotnik descends a tube as you progressively defeat his different machines.
2. The blue "HIT THESE, STUPID" lights are plainly obvious.
3. Robotnik employs three different machines: two guns, two flamethrowers, and then two guns that spray every which way.
4. However poor your perspective (Sonic 3D Sonic Isometric Blast) is, don't panic (puppet): after this is the final fight. This is the penultimate boss.

I had to look it up, but I think its Mecha Gorilla from Sonic Labyrinth.

1. Attack of the (mini) Clones.
Battle begins with little robot monkeys

2. Rayman, eat your heart out.
He shoots his arms out at you.

3. Is that Chaos Control?
He only appears after the wave of little monkeys.

4. Slow down, hedgehog!
The whole game features a slow Sonic.

If this isn't it then this is totally not fair TT_TT

Sorry for just drifting out of here on everyone- this actually slipped my mind, but I felt it worth saying that, just for the record, that is absolutely right. So you didn't JUST win by default, Blue, you got it fair and square.

Not that it matters at all save for bragging rights at this point, but hey, felt I owed it to ya to let you know.
  

1. STOMP STOMP STOMP STOMP
2. I still have these missiles at least!
3. This probably wasn't the best place to deploy such a creation...

Tails' final boss from Sonic Adventure?

Dang Kayla, you on fire girl!

Yep, you're right. Tails's final boss from SA.

w00t!! Okay...

1) Where'd the Slowbro go?

2) Definitely NOT a girl's best friend

3) Penultimate

Bumped to keep from falling off the first page.

Methinks the lack of replies is indicative of a need for more clues, Kayla :O

Kay.

4) "_________ in the Sky" of a certain jeweled race track

...well now I'm even more confused. o_o That last clue's a definite reference to Sonic R's Radiant Emerald, but that doesn't have a boss, or a challenge race, nor is it the penultimate level of the game.

This isn't a roundabout reference to Mecha Knuckles from Sonic R is it?

Well, 2 and 4 very pointedly suggest diamonds, if that's any help...

Rapid's on the right track. The boss in question has nothing to do with Radiant Emerald, but it's BGM does.