I have a lot of respect for the Metal Slug series, but I could never spend a whole lot of time with it. Initially this was a financial problem, as the difficulty the game mixed with my frugal nature made dropping tokens into game that could kill me five seconds in a risky decision. When emulators came around, the Metal Slug games were something of a short term distraction. They are ruined by free play, because it removes any incentive to get good, and I always end up mindlessly running through the game. It has given me an appreciation for the art and the spectacle, but not finesse of actually playing.
Metal Slug 1st Mission is the first Metal Slug for a portable system, and it does a pretty good job of scaling down the Metal Slug experience. It very accurately reproduces the arcade game's mechanics, though the NeoGeo Pocket Color's hardware requires a slight change in the controls. With only two regular buttons and an option button, you get the obvious jump and shoot, but the option button toggles between regular fire and grenades. It's not an elegant solution, but it works. Once you get used to that, all your jumping around and killing techniques will work just the same as they would in the arcade games.
The biggest problem with this game stems from the hardware limitations of the platform. One of the most charming parts of the arcade games is the extremely well animated and comical/gruesome animations themselves. While the sprites are clear and accurate representations of the arcade originals, they are missing a lot of the character. It is not all bad though, it retains the over-the-top action, leading you into various vehicles and crazy situations. The controls are spot on, and shooting and movement are very good.
A major difference with 1st Mission is the continue system. Instead of one credit giving the player a few lives, you get a life bar. I'm sure this change irked some of the Contra fans out there, but for less skillful players such as myself it is helpful. Conversely, dying returns you to the beginning of the stage instead of allowing instant respawns, which is less appealing. On the positive side, there are item pickups that refill health and give you extra continues. Metal Slug 1st Mission is a solid game, but like many NGPC titles, it isn't just “great,” but “great considering the limitations.”