Got there in the end.....
Uploaded to the Zone are three savestates.
File RI12 is level 12 on Monster Island after defeating the boss.
File RI13 is level 13 on Toy Island. As you will see the graphics are corrupt but by moving your character to the right, you disappear off-screen, then the screen scrolls to the top and auto-completes.... weird.
Level 14, 15 and 16 within Toy Island play fine with no glitches.
But, the most important savestate of all is...
File RI16bossbeat, is self-explanatory....
Then on loading Doh Island, at the start of level 17, the game goes tits up and crashes.
Let me know how you get on....