Let's make fun of sprites from Pokemon RGB!

 Red and Green

Venusaur - "I has a tree on my back!"
Charizard - "I'm getting my hands on fire!"
Nidoqueen and Nidoking - "We eat at McDonalds"
Wigglytuff - Look at her eyes, they look inaccurate.
Vileplume - The plant on its head is off.
Diglett and Dugtrio - The nose are small and they look lime mouths.
Gengar - "I'm a fat ghost"
Hitmonchan - Censorship much?
Rhydon - Obviously looks like a Nidoking from Blue version.
Dragonair - Looks like he has a nose.
Mew - See the image above.

 Blue

Note: These sprites were also used in the NA and PAL version of Red.

Ivysaur - wtp Why is he standing?!
Blastoise - "I also eat at McDonalds."
Kakuna - His arms are sticking out of his shell
Pidgeot - "GTFO papayas!"
Nidoran (F) - "I look like a hamster!"
Vileplume - See Red and Green
Machop - "Don't even ask me."
Graveler - He looks like he doesn't have any legs
Slowbro - He looks like he's eating Shelder.
Magnaton - OMG What happened to the one on the left!?
Cloyster - His shell was turned sideways.
Kingler - Both of his arms look identical to each other.
Exeggcute - "I'm the biggest egg out of all of you guys!"
Koffing - Both his face and mark were switched around.
Weezing - The left and the right got switched, and it looks like the left one is eating the right one.
Moltres - "I look like a derp!"