Yeah, it has Metal Slug 1-6. Complete with the bizarre loading times that the review warns about. But it doesn't have a few other features that the review and the manual indicate it does.
The manual does warn that it was prepared using a preliminary version of the game that may differ from the finished product. And differ it does. I know this is fairly common, but one of the features I would have bought the game for was not included: saving during a game. If you exit a game, you have to start all over, and as far as I know, there's no way around this. Certainly no "save" option anywhere like the manual depicts. What's worse, the game doesn't even save your high scores! What is the point of this being anything other than a rental without at least a save scores feature? I don't see it, and that's why I'm glad I decided to rent this game before buying it.
About the only thing you can unlock is art, and none of it was all that exciting for me. I finished each and every game in the collection and ended up paying an extra day's rental fee because I slept through most of the last day I had it and couldn't get it back before 7, and all I got were some lousy pictures. I did get to play as Ralf and Clark in Metal Slug 6, and that and some of the prisoners you get to rescue in that last game are worth the price of a rental admission, but once again I'm so glad I didn't buy the game new. I might actually consider it very carefully if I see it in a $5 bargain bin at some point.