The Combatribes

I always enjoyed beat 'em ups back in the day. Final Fight and X-Men and TMNT in the arcade were some of the best games ever. Still hold up to this day. MANY MANY MANY beat 'em up clones were made back then to fill every arcade in the world it seemed. I never played this one as a kid, but it's been released a few different times over the years for SNES and Wii, and it's currently on the Evercade on the @technos-arcade-1 collection.
What's nice about most of these arcade games today is that you can just push *SELECT* to add another virtual quarter into your console. If I had to play this all the way thru when I was 10 years old, I would have probably pumped well over 100 quarters into this game. It's brutally hard, the enemies never stop attacking you, and can get frustrating. However, it does look amazing. For a retro beat 'em up in 1990, the graphics and sound and characters are incredible. You don't really have any special moves (like pushing punch + kick at the same time) so the combat definitely is limited and repetitive.
It's about 6 levels of swarms of enemies all attacking you, sometimes 6 or 7 at a time. So it definitely seems a little unfair. But with it only being 6 levels you could push thru it in just about an hour or less once you get the hang of it (and unlimited quarters).