Streets of Rage is a good beat-em-up, yes. However, Streets of Rage 2 is the better alternative.
The entire time you go through 8 stages, fighting various enemies along the way to the final fight with the boss of the level by yourself or with a friend in co-op mode. From there you can use certain areas of the environment to find either money for extra points, food to replenish your H.P or pick up items to use on enemies. The gameplay is pretty straightforward, easy to get into and with 4 various difficulties to test your might, all is right in the world......thus far.
Control wise is either from the Wiimote sideways, Classic or GameCube controller. On the Wiimote, the "1" and "2" are your attack (action) and jump buttons respectively. The "A" button is your full-screen kill button. Pressing it will summon a police car that fires a rocket into the air and obliterate all enemies on-screen (it will heavily damage bosses, especially the 5th stage boss which is THE most annoying one in this entire game). While it is a good assistance to help you get through the more tougher areas of the game, you can only use it once so think wisely before you waste it.
All in all, Streets of Rage is a pretty decent start to what many consider to be the best beat-em-up series of all-time. However, there is a reason why this game in the series is not mentioned: in comparison to its sequels Streets of Rage 2 and Streets of Rage 3, it lacks a lot of depth. Now don't get me wrong, it is still a good game by its own rights. It just doesn't hold up to its later titles. If anything, buy Streets of Rage 2 over Streets of Rage 1 as that game is easily the best of the entire series.