Authentic looking EGA graphics?
Check

Authentic sounding PC speaker music and sound effects?
Check

3 MiB total download size?
Check

DRM-free?
Check

Portable game code?
Check
(You can bring it around with you on a USB drive or go really old school and compress it to fit on a floppy diskette.)

Apogee-style platforming action?
Check

Saves your high scores?
Check

If this list sounds good to you, then *ahem* check out MURI, a 2013 Windows game release that feels like it belongs in the 1980's with the games that inspired it. Just a fair warning, though: you cannot save your progress as you play. Unlike its inspirations, this game decided to go even more old-school than that and will only save your high scores for each of its four episodes.

Each episode has five stages, so the game has a total of 20 levels in all. Playing through all of these will take about 2 hours for a full play-through. However the game has many difficulty levels which add to the replay-ability, and they bring the total play time up to four to six hours depending on how good you are. I think that's a pretty great value for a $3.99 game. And the main theme music is still stuck in my mind!