Just wonder did they ever fixed up Twin Dragon with level 11?

i remember playing it couple of years ago and you get near the end of the level and the exit button didn't work.

Are you referring to Hung Lo's Fortress (in addon order Mission 11) or to Toxic Waste Facility (in episode order Mission 11) because both of them are possible to finish in version bundled by GOG.

Strange you even mention something like this, it was kind of beta with messed files or wrong installed? Because no known issue apart from impossible secret on lower difficulties at level 6 is in Twin Dragon (Wanton Destruction had problems with spawning mini-boss and boss enemies on two levels if difficulty is set below 3-4).

Code Of Honor -> Twin Dragon
Level 5. Rising Son -> Wang's Home---$whirl.map
Level 6. Killing Fields -> City Of Despair---$tank.map
Level 7. Hara-Kiri Harbor -> Emergency Room---$boat.map
Level 8. Zilla's Villa -> Hide And Seek---$garden.map
Level 9. Monastery -> Warehouse---$outpost.map
Level 10. Raider of the Lost Wang -> Military Research Base---$hidtemp.map
Level 11. Sumo Sky Palace -> Toxic Waste---$plax1.map
Level 12. Bath House -> Crazy Train---$bath.map
Level 13. Unfriendly Skies -> Fishing Village---$airport.map
Level 14. Crude Oil -> The Garden---$refiner.map
Level 15. Coolie Mines -> The Fortress---$newmine.map
Level 20. Stone Rain -> The Palace---$volcano.map
Level 21. Shanghai Shipwreck -> Prison Camp---$shore.map

It was the Fortress level

hmmmm okay they've fixed it up it seems from what your saying.

Based on my experiences (Shadow Warrior Complete with DOSBox 0.74) playing on who wants wang or no pain no gain I completed it without problems. Since Fortress (15) jumps immediately into Palace (20) any messed $volcano.map or bad reference to next level will probably stop progress, but it's in separate folder so replacing files by accident is unlikely however possible (because it's not compressed into one .GRP fie but unpacked one. Apart from above you need turn the music on due to edited executable with level names and other stuff everything works fine.

PS. Just to make sure I no-clipped whole level on ghost mode up to the exit area on second difficulty (I have no fear), the screenshots speaks for themselves. It works fine without any fixes or cheats. Attached.