Try that patch please:
https://1fichier.com/?lh6nmvuqj2tw1n52oq6r
I use the color 8 for the scorpion and 12 for the frog, and on MSX2~ i use the colors palette to make it look like the Atari 2600 version.
While playing around for a bit, I noticed a sprite collision bug with the Electric Eel. The player's foot even got deformed once while descending a ladder. So you're right, there are a few sprite bugs happening but it's rare.
While playing around for a bit, I noticed a sprite collision bug with the Electric Eel. The player's foot even got deformed once while descending a ladder. So you're right, there are a few sprite bugs happening but it's rare.
I forgot to specify that it was on BlueMSX. So it is not yet certain that this happens on a real MSX.
There is screenshot with original colors:
I played until the end with OpenMSX using save state. No sprite colision bug, only the player sprite bug has happened (quite often) when descending a ladder.
It seems that sometimes one byte too many is sent to the sprite.
For the 2nd patch, the dark blue background and change in Harry's cloths made it very difficult to see Harry walk, and the parts with the scorpion slowed down a bit (only tested in BlueMSX) ...?
The 1st patch was perfect for me, many many thanks 
Oups, 8027h instead of 8028h.
Here is a screenshots of the Atari 2600 version:
I must have done less greenish because of the palette and the other colors and graphics that are not placed the same.
PS: Score color is at 009Fh. (07h for black, F7h for white)
Many thanks