I'd like to say before listing the pros and cons that I absolutely love this game. Definitely worth getting.
-Simple yet very challenging campaign.
-Multiplayer is utilised well(you can't get into secret levels unless you co-operate with teammates)
-Fluid gameplay, nothing really strange happens under normal conditions.
-Very nice graphics and in-game music
-Almost zero random events which kill you like in most platformers
-Multiplayer can be very glitchy when the ping between you and the player is higher than let's say 100ms(bullets curving from their paths rather than being delayed...)
That's all that I can think of for now! Also, one thing to note. You should definitely play this in multiplayer. I found myself playing the game and enjoying it a lot more with others. Sometimes it isn't fun failing over and over unless somebody is doing it with you!