why portleg is illegal?

[PontrolCoint]

i want to know, (for a reason) why the portleg illegal?

 

[ArpeggioPegasus]

Because usually, the quality of said portlegs is really dubious (as in, there's usually little work involved in actually adapting old mods to the current version of SRB2 correctly), they don't fit within the current quality standards due to outdated visual and game design choices, and go against the will of those who originally developed the mods in question. If someone who created a mod for a previous major release of SRB2 ever feels the need to bring it to the current version, they'll either do it themselves or give someone else their blessings to do it.

There's no such thing as "illegal portlegs" though. It's fan-made content for a fan-game. It's just a matter of respecting someone else's work.