First things first, I think it's been over 16 years since the last time I played this game and I can hardly remember anything about it so this will probably be really bad information.

Ok so, it was for nes, and if I remember right it had 2 player mode(separately, not same time).

I think the levels were all indoors. In the levels you travelled upwards by this string(?) you shot at the platforms and way up high you eventually came to a door that was the end of the level. There might have been enemies too, somehow I seem to think there was these shadowy characters every now and then that you had to avoid, but I'm not really sure, I might be mixing it to some other game.

If I remember right, some of the levels(or maybe they all were) were kinda party themed.  And I do remember the music the game had even after all these years, unfortunately I really cannot write how it went ;l.

It's not Rainbow islands by the way or anything like that.

This is a bit broad, do you know which system it was for?

Very difficult to pinpoint here. Along for what system it is for, do you happen to know what you played as? Were you a human, animal, etc.? Just knowing what you played as could be the most important detail.

It was for 8-Bit Nintendo(nes), and you played as human. Also now that I think of it, I think the "string" you used didn't go straight up so you needed to be on left and shoot it to right(or be on right and shoot it to left) to get to upper areas.