Great idea that's going to supply the roots for lots of games to come!
So the game offers an interesting concept that a lot of games do these days: completion. In each level, there are five banana coins to collect. At various multiples of 5 (so for us non-math individuals, that would be 5, 10, 15, 20...) you can unlock various perks. My one gripe with task based games is that it requires everything to be done (here, finding all the coins) to advance. Jungle Climber doesn't do that, which is a great thing. But the perks available do help the final clash.
Throwing Diddy Kong? Well, I'm sure PETA objects, but I've wanted to toss him about since he lost Donkey Kong's banana horde in the first game! Overall, it provides for some really great game play.
Side scroller? Well, on one hand it is, but inherent to the DS alone is the availability of two screens. Jungle Climber makes some use of them, but I wouldn't go so far as to say it does a great job. Rather, they tease us a bit, using it for puzzles with Diddy Kong.
As far as the specs, it took me about 10 hours or so to beat this game (which I find is consistent with my fellow raters). The learning curve is maybe a half hour, which is normal for most games. It makes good use of all of the DS controls, and its got a decent amount of worlds.
Overall, its a great glimpse of what's to come. Is it good? Yes. Is it great? Parts are, yes. Could it have been better? Sure, but everything has room.for improvement. With enough variation and novelty magic, Jungle Climber definitely has its merit.