> > Moon Patrol. Like the arcade game of the same name. Pretty good.
> >
> One of my favourites on my C64. It was the first game on the first side of our first floppy.
>
> > Munch Man. As mentioned, a Pac-Man clone. Only, you lay chain instead of eating dots. The nice thing about this is that the hoonos (who-knows) have different shapes depending on the level. Also, it gives you little encouraging messages when you complete a level.
> >
> I just couldn't wrap my head around level 9, where the walls were invisible. But my dad finished it, and he wound up on a harder level 1. Bit of an anticlimax.

This got me thinking about Commodore 64 games. One of my favourite "hidden parts" in a Commodore 64 game is in "Wizard" by Progressive Peripherals & Software.
In the level "Ladder land", the topmost gold ball is guarded by an invisible enemy. Get a key to gain some spells and shoot at the ball to kill the invisible enemy. Then go to the top of a ladder and jump to the platform with the ball.
The ball is in fact magic - and its magic effect is to recreate itself, in the exact same place. So you end up getting the same gold ball over and over again, for as long as you like, amassing points while you wait. I have managed to score over ten million points and get about 30 extra lives this way.