I play Smash Run a lot, but I can kind of see why it gets some flak.
For one thing, one major step down from City Trial is the fact that you can't interact with the other players on the same map. Everyone is just running around in their own little world, isolated from each other. Part of the fun of City Trial in Air Ride was hunting down the other opponents and stealing their stat boots. To be fair, I get the feeling this was done was because of technical limitations of the 3DS. I've noticed that when a bunch of enemies spawn and you run away from them, most of them despawn, and more enemies appear where you're at. If there were four players on the same map together, enemies would just keep spawning left and right and perhaps that'd train the CPU down or something. The devs already had to cut corners to make Smash work on 3DS, like neutering the item frequency option, making NPCs move at 30 fps, and unfortunately, cutting the Ice Climbers, so I wouldn’t be surprised if that was the case.
Secondly, the lack of options is also disappointing. City Trial gave you a bunch of options for the the city segment and the final battle, like how much time there is and what the minigame at the end revolves around. Smash Run gives you none of that, basically only allowing you to run around in the maze for five minutes and always end with a 1 minute long battle/minigame. It especially sucks that you can’t select the final battle, because, well, say I’m Little Mac, and I get a 1000+ boost in attack power, and naturally I’d want to show that off in a regular Smash battle, right? Well, too bad, I have to play the damn climbing minigame.
And then lastly…I think most of the enemies themselves in the maze segment are generally too crazy and frustrating to deal with. This is a similar problem I think SSE had as well. Half the time, you’re just being gang ***** into a corner by all these enemies that have like, gigantically long laser attacks or enemies that get you stuck in place which allows others to ram into you with their powerful attacks that send you flying, usually KOing you. The Devil Car, Chandelure, Skuttler Mage, Petili, Egg Robo, etc can all go suck a ****.
But despite all that, I like playing it every now and then. It definitely becomes more enjoyable when you make more use of equipment, custom moves, and powers (Brief Invincibility is your friend), and it’s still pretty funny to get a crapload of attack/special stat boosts and destroy everything insight.