It's Metal Slug and alot of it. 6 1/2 great games for $40 can't beat that. Best in the series because it is the series.
So anyways like the good old fashioned arcade games its something you'll get good at then get competitive with memorize all the levels try to go back and get perfect scores etc.
These games were arcade games so they'll only take about 30-40 minutes to beat for an unexperienced player (who has unlimited continues, I can't see many comleteing these games in under 10 continues (which is the "hard difficulty.).
Graphics and sound are alright Metal Slug 6 obviously looks best with lots of extra little details. But these games aren't don't really go by graphics and sound to judge how good they are. There's never a bit of slowdown that I've noticed, and the action can get absolutely ridiculous, I bet only the die hards can keep up with it. Sound is prety bad sound clis aren't great quality its just blah, music is fine and fitting though.
The game play though is timeless and having all these games only makes it so much more valuable. While I haven't unlocked everything it seems to be lacking a little in that department. Shouldn't take long to unlock everything.
However again the value here is playing through all these games with a friend (up to 3 other friends) and then playing it with them on harder difficulties and then getting higher scores, and then trying to go without using a continue or something insane like that. That's what Metal Slug is all about and it's very good at it.
An awesome compilation with every game playing just as they should. Solid. Lots of replayability, great with friends, great to master alone, and the one thing I have yet to mention is it has many whacky uses of the Wii controller that make it very fun. You can also plug in a GC controller if you think that would be most comfortable.