A StreetPass feature allows you to download Pokemon from anyone you encounter on your travels to fight in a boss battle. It's the kind of idea that sums up Super Pokémon Rumble in general - a fun novelty at first, but incredibly limited.
All that said, as you approach the endgame - and even beyond - things do improve. Type advantages, of minimal importance throughout, suddenly start to figure during the tougher challenges, and especially during boss fights.
By this stage, you'll have a number of Pokemon with decent special abilities, some able to regain health and others dishing out damage much quicker. Eventually they'll become less disposable - you'll likely have a select group of powerful fighters with superior moves that you'll chop and change between depending on
the enemies you're facing. It's perhaps telling that Rumble is at its best when it feels most like a real Pokémon game.
Filling your Pokédex is a task that will likely be beyond anyone without the patience of a Buddhist monk, but given the lack of the original game's four-player mode, that's where the real longevity lies.
Otherwise, Super Pokémon Rumble feels a little too thin for a full-price release. Its snack-sized stages make it a decent fit for portable play, but we'd sooner have seen this as a headline act on the 3DSware service, not gracing the same shelves as Mario, Link and Fox.