Really entertaining! I had it for a month and I'm still playing it with my cousin, her little sister and some friends who end up coming to her house.
I believed the game is more fun when you play with friends. It is possible that there will be arguments such as:
"omg!! why did you toss me in the lava?"
"Hey You stole my yoshi!"
"Arrgg Ima get you!!"
"MOVE SHAMIYO-SAN.... YOUR BLOCKING THE PASSAGE.....AFFGGHHH BOWSER COMin.....DANG HE KILL US, WHY YOU BLOCK?"
"no...coming.no...NO NO NO.... (!) Yes.....Whew! I survive"
-- " What? I didn't. You JUMP ON MY HEAD!"
etc. etc., when I played with my cousin, my cousin little sister, and a couple of friend (sometime take turn) We yelled soo much in excitement, our parents told us to quiet down 8 time! I have to admit.....I want to yell not because i am mad, but excited with laughter and surprise. I end up shoving papers in my mouth and make yelling moaning noise

. Anyway, just explain, or learn that people should not be seriously upset about the game. Arguments is possible.
The game is fun. It isn't online though. There pros and cons when working by yourself and working with partners of 2, 3 or 4. Working by yourself means no distraction, no interruption, and no screen movement by partners. However, one death and you'll start over unless you touch a small flag/checkpoint.
With Partners, it is fun and hey...... I laughed. One time, my friend was playing with his brother, grandma, and their little sister. I loled @ grandma when they tried to teach her how to play and get to the big flag. Turns out she never died when she reach the flag and my friends keep on dieing. Pros for having Partners is that if you die in a map, you will survive if your partners do not die ( and if there are any life points left).
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I suggest Secret World map 9-3 and 9-8, and a map somewhere in world 5 and 6 cave map. I am not at my cousin house, but I think World 5 have a map with a small pond with a platform on it. It is fun with partners because monster are on top of the platform going down on to your "platform boat" as if they were pirates. Better scream "MAN TO BATTLESTATION?"
In world 6, the bullet bill map, the cave is a dark cave. There is a small boat with a light you can control. Not much monsters though.
World 9-3 have bullet bills chasing you.
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World 9-8 is the grand giant bullet bills of all map.