My initial impression of SNK Playmore's Metal Slug 7 was that it was a little bit bland for a Metal Slug game. It certainly lacks the personality and irresistible wackiness that characterize pretty much every other entry in the series. Compared to the DS's other big run-and-gun game, Contra 4, which not only revived, but improved upon its legendary legacy, Metal Slug 7 is a bit underwhelming, a competent imitation of other Metal Slugs at best.
After more playtime, however, I found that the imitation is accurate enough where it counts (mostly the controls). Even in its diminished state, Metal Slug is irresistibly fun.