I think it's been long enough now, so here is the complete walkthrough for anyone who wants it:
500LIZM – The 500 Islands
WALKTHROUGH
1. Stinky: Step down and jump up. Push top box L in water, and lower box D. Push right box D onto conveyor and follow. Push box R over tramp and it will land in the water. Tramp R, R, U. Collect coins and activate red gate to bring z-bot to the top alley. When z-bot goes left, quickly step left and down. Tramp R, R, D to get bonus in cave. Tramp U over wall and push box D through red TP and into water. Ride raft around the top right area, collecting coins and finishing at the palm tree by the cannon.
2. Walk up and tramp up into the cave. Push left box D into water and right box R over tramps. Go back to the raft and ride up to collect the coin on the island. Leave the raft there. Walk round to the top of the pond and tramp down onto the raft. Collect coins and ride U, R, D, R. Push cannon 1xR and let it smash 2 boxes, then push it 1xR again. Push last box from that row 1xD, step round and wait below and right of the box.
3. Loof: Push box L below break tile, push Stinky’s box D in front of him. Walk round and push the box at the bottom of the pond U into the water and walk back to wait on the break tile. Switch back to Stinky.
4. Stinky: Push box round to the bottom of the pond to continue the bridge to the generator island. Walk back to the alcove at the bottom right. Switch to Loof.
5. Loof: Push box round to continue bridge. Walk up to the top right raft and ride down to the palm tree to push the cannon 1xL. Ride the raft up again and push cannon all the way down to Stinky. Switch to Stinky.
6. Stinky: Push cannon L to blow up right side box. Collect coins and push last box up to complete the bridge. Generator starts. Collect bonus coin and push cannon up to bonus coin spot, using the little island to avoid cannon fire. Go and stand in the bottom right alcove again. Switch to Loof.
7. Loof: Walk to raft near reflector. Ride L, R, D. Push reflector 1xR and all the way D to Stinky. Then get back on raft to ride L, U, L, D, L, U to wait by the green spheres. Switch to Stinky.
8. Stinky: Push reflector below cannon to keep the green timer activated. Take care to avoid cannon fire from reflector. Jump L over lower left tramp. Push the sphere U, take the coin and push it U again. Ride the raft L. Switch to Loof who can now go through the gate and ride his raft L.
9. Switch to Qookie: Tramp D over red sphere and push it U. When it bounces back down, go left and push the pink cube L to cover the pink button. Don’t take the coin there. Push the sphere in the pyramid R, which sends the top sphere R to bring the raft L. Walk round, take coin push sphere L. Walk back to tramp at left side of pyramid and tramp L which lands you on the breaktile near the pink cube. Push sphere up and when it lands in the water, follow it. Take bonus, ride R, D to get bonus in pink cube. Ride U and go through tunnel to get bonuses at top. Ride L and get time and bonus, quickly running back to raft.
10. Ride D, L, U, R. Get bonus from cave when z-bot goes right. Get extra time from lower caves. Ride L, D, R to shark infested waters. Ride U, R and push the boulder R thru TP. Ride L, R, D, R and push the boulder U thru TP. Follow and push cannon L thru TP. Leave it to do its work and ride R, collecting all coins and leaving the raft parallel to the ice cube. Push ice cube L, U. Use raft to help push it R to get the bonus coin. Ride back to the green TP and go L through it to push the cannon 1xL. Ride down and wait on sign.
11. Switch to Peegue: Barrel in water, travel all the way R collecting coins etc. At the last tramp jump R, U to land on sign. Then ride down and do nothing until you land on the yellow timer. Quickly push the barrel D in the water and wait on the island for explosion. When safe step on yellow timer and go into kaboom room to push the boulder D and get out, stepping on the timer again. The kaboom blows up the last barrel. Step on timer again and push the yellow sphere L, quickly following. Step on timer again, yellow sphere U and L thru TP, step down. Go right again and push boulder onto blue button.
12. Down thru white TP. Push the pink sphere L thru TP and follow to push it 1 further. Back thru TP and push boulder L to block it. Through TP into the coin area. Push left pink cube U below TP. Push right pink cube U beside it to block TP. Go L and ride raft U. Push lower pink cube and boulder R into water. Repeat with upper. Collect coin and ride D. Push steel box 1 down. Push boulder R and walk L to tramp R, R and push the box U left of the ice to block the boulder.
13. From where you are standing, tramp L, D, L, L to land on coin. Push cube/boulder D into water. Tramp R, R, R. Take coin, push prisms into water and raft R. After cannon fire push barrel R and ride back quickly to hide behind the wall. When the prisms have blown ride R again. Walk up to the remaining 3 prisms and push the left one 1xD and 2xR. Step up. The last prisms are blown and the cyan gates open. Avoiding cannon fire collect remaining coins from Stonehenge and exit.
14. Qookie, Stinky and Loof can now exit too.
This set also includes a waterfall by JanetGalle. Thanks so much Janet! 
