Liquidator 2: Welcome to Hell

does anybody know how to fix checker antipirate protection underwater?

Here are some helpful infographics that might help anyone play this and fix visual bugs:
https://cdn.discordapp.com/attachments/810405089754873906/938711895135907910/Liquidator_Help_1.png https://cdn.discordapp.com/attachments/810405089754873906/938711915901907004/Liquidator_Help_2.png https://cdn.discordapp.com/attachments/810405089754873906/938711928342212718/LiquidatorHelp_3.jpg https://cdn.discordapp.com/attachments/810405089754873906/938711941524881428/LiquidatorHelp_4.png

An OK shooter where you kill monsters and ogres. 3 large levels and same weapons at start. Everything works on and I played on Windows 7 64-bit. The only downside is the underwater swimming bug. There comes this annoying error texture as overlay making it nearly impossible to swim in the right direction. This is necessary for solving a puzzle for unlocking a door for example.