Missile, if you like Beat em Ups and environmental interaction, check out other Technos' offerings beyond Double Dragon, such as Kunio-kun no Jidaigeki Dayo Zen'in Shuugou (Famicom), Kakatou Densetsu (Famicom), Shadow Force (Arcade) or The Combatribes (Arcade).
Relevant videos for what has been discussed the past few posts.
Personally, I'm a big fan of The Karate Tournament which boasts a relatively limited moveset (and only 1 character), and also has some of the simple design elements discussed in the videos (do nothing to block, segmented health bar). Different topic, perhaps, but there's something to be said that you can take genres which are typically complex and simplify them to create intense, meaningful, games. There's no reason you need to be a human or beating up humanoids. There's no reason you need to script AI when you could have human controlled opponents. You could rip out a lot of things typical to a genre and still make an enjoyable game.
But why not? Maybe we're too busy imitating what we know. There's a saying, "First you imitate, then you create". But we're trying to imitate finished products too soon - games that had years of experience building related simpler problems on their backs. We're not good at judging scope and difficulty, and so there probably are a lot of homebrew beatemups. . . unfinished.