I have been a fan of the side scrolling, action packed, white knuckle shooting games since the first time I looked at Konami's Contra! And this genre of 2D shooting bliss has come into fire for it's unoriginality and repetitious game play, but there is hope. You see, just as long as games like Metal Slug continue to be released on consoles and in the arcade there will always be hope.
The greatness that is Metal Slug does not come in it's overwhelming control ... in fact, the control is the worst part of this game. But where that would be a glowing problem, Metal Slug more than makes up for it's weakest link by constantly throwing original backgrounds, strange levels, and interactive foregrounds like no other. It's only when you really need it that you notice that the programmers weren't nice enough to give you a diagonal shot (something standard in every shooter since the 80's).
Being the first Metal Slug, the creative team had yet to develop the "alien" story that would later dominate the series, and this little note is a little more important than you might think. The entire game felt a little absent of something, until I realized I was only fighting the opposing forces. Even the last boss is pretty lackluster, especially being the standard of quality set through the first couple of levels.
You can only choose one character (two if you count the second player) and there aren't very many weapons to aid you on your trip. The game isn't difficult, though not easy, either, but more weapons would have been nice. And there is only one vehicle to hop into ... though that one vehicle let's you shoot in diagonals!
While the game is a little more limited than it's sequels, it's well worth playing through. It's just as much fun now, and you might enjoy it even more today than you would have at it's release. In a time when you can't find games like this anywhere, this game reminds me why 3D isn't ALWAYS better.