X-Men Legends, X-Men Legends 2, and Marvel: Ultimate Alliance. - I loved these games because of the character customization and the co-op beat-em-up gameplay. If you want to know what I dislike about the series, look at my Ultimate Alliance review.
Shinobi (Sega Master System) - The game is piss easy, except for 3 levels near the end, 2 of which are difficult because of damn hard jumps. It doesn't help that pressing the opposite direction of where you're facing will not just make you turn around, but make you take a step in that direction. Not good for pixel perfect platform jumping. The other level provides is more of a challenge in memorization (or crouching and walking slowly), with crazy ninjas jumping at you from offscreen every few steps.
Ghostbusters (Sega Master System) - Catching ghosts is no real challenge at all, and that's pretty much what you're trying to do for 75% of the game. The last 25% is spent slipping by the Marshmellow Man as he jumps around in an attempt to guard the entrance to the Shandor Building (or "Zuul" as it's called in the game), Walking up the tower while shooting ghosts (sometimes they spawn a floor below you and you can't shoot downwards), and having a showdown with Gozer (or "Gorza")
7th Legion - My first RTS, so I had nothing to compare it to, really. So many things wrong with it. Basically, I was pretty much invincible in any campaign mission where you start off with a base. There are about only 5 or so where you don't. Buildings appear out of thin air when you buy them, the two factions are nearly identical, the AI is retardiculous, and there's this card system where you use "Battle Cards" for various stuff (they work like God Powers in Age of Mythology), which is interesting, except what you get and when is completely random.