Xiao Xiao 9 I used to feel tortured as a kid by this game because I couldn't beat it until I was older. I know it was made over 20 years ago, but to this day I still find it extremely frustrating because I came back and played it again.
The enemies' life bars are way too long and you'll end up getting stuck as they all gang up on you. The one way to escape (the spin kick) takes your health away.
Your main attack is so terrible and weak that sometimes I'll wait for the enemies to get stuck behind a wall and moonwalk away from me before I even attempt to hit them. If you tap your attack key slowly in rhythm you can just keep doing the main punch instead of knocking the enemy down and waiting for his slow ass to get back up.
Also, don't even get me started on the boss fight at the end, it's ridiculous. The guy has 4 health bars, and auto-attacks you if you step too close to him. There's no challenge in being beat to death automatically. I find that using the jump kick over and over and over again to beat him works, but it takes like 20 years off your life.
At least the game was always gracious enough to let you have 10 lives.
Dummy Never Fails 
IceScape 2 
The Gun Game 
TOM FULP DRESSUP 
The YTP Soundboard 
Clinically Obese SMB 
Stunt Bike Draw 
Zombie Exploder 
The Last Stand.