Seems that I have on a good number of occasions. In my own opinion anyway, I can understand that some of you may think differently, and this is completely understandable. Finding retro gems is a matter of opinion after all.
One that I came across recently on the NES is "Felix the Cat".

Watch Youtube Video:
https://www.youtube.com/watch?v=V2UQEGOwzIY
I've come to find out that this is actually based on an old cartoon,
and checking out several others that were put in the same situation, this often doesn't end well.
This game is a rare exception.
Taking in to account the console hardware that this game is on, the audio is actually quite good.
The graphics aren't too bad either, considering. Near as I can tell, they remain faithful to the styling used in the cartoon.
With 9 worlds to go through to boot.
Overall gameplay has proven to be an intriguing factor,
this game's engine is quite well made, given the era it was released,
You gain powerups by collecting these Felix head tokens, after so many, you will either get a heart, or 3 milk bottles.
Pick up the heart to upgrade your current powerup, and with it, your health meter.
Yes, much like Mario, your health is determined by your current powerup, but this goes to this goes a step further.
You have your current powerup for a limited time, measured by 2 rows of hearts, once these are depleted, you go back to the previous.
If you upgrade, or take damage and downgrade, this meter is refilled.
There are actually 4 powers available.
In order from no health to max health:
Magic Bag, (Which is apparently one of those giant extending boxing gloves.)
Stars,
Car,
Tank.
These powerups change depending on the level type you are in.
I am actually unclear on the games storyline,
I think the bad guy is after Felix's magic bag, and has kidnapped his girlfriend, or something along those lines.
I have yet to complete this game,
but from what I've seen so far, I think that I would definitely recommend it to anyone who is in to retro titles.
For more information, See this Wiki article.
Have any of you found any retro gaming gems?
If so, why not share it with the rest of us?