Hi, this might not work for all of you, but I managed to solve the invisible dynamite/knives glitch. I contacted GOG support and that's what they told me to do:
"Please try these troubleshooting steps:
1) Please make sure that you use "Run as Administrator" to install and to start the game (right-click on the shortcut or setup file and select "Run as Administrator"). If you are using Galaxy, then make sure to run Galaxy as Administrator.
2) Please reinstall the game AND add it to your anti-virus/firewall software's exception/trusted list. Simply disabling firewall or AV software could not be enough, since some of these software are running still in background or in services list. If you are using Galaxy, then please add Galaxy as well.
3) Reinstall the June 2010 DirectX runtime package, then use the DirectX web installer.
You can find the archive file containing the 2010 package installation files here: http://www.microsoft.com/en-us/download/details.aspx?id=8109
You will have to extract the files into some folder, then open that folder and launch the DXSETUP.exe file in order to proceed with the installation.
Afterwards, download the latest DirectX web installer and use it as well: http://www.microsoft.com/en-us/download/details.aspx?id=35
4) Using an unusual DPI setting has been known to cause problems for some games. Please follow these steps to reset it to the default value and let me know if it helped:
I) Right-click an empty section of your desktop and go to “Personalize”,
II) Click “Display” in the bottom-left corner
III) Change your DPI setting to '100% (Default) and confirm by clicking “Apply”.
5)Try disabling DSR: http://www.gog.com/support/support_view/potential_issues_with_supersampling_dsr_factors_feature_on_highend_geforce_cards
6) Please update your graphics device drivers: https://downloadcenter.intel.com
7) Your DxDiag report shows that you're using an integrated Intel video device. Please go to NVIDIA Control Panel and there to Manage 3D settings. You should be able to select the NVIDIA card as the preferred device or create a profile for the game to use it.
8) Please try changing graphics mode. Right-click on Outlaws shortcut on your desktop and select "Open file location" form the drop-down menu. In there run config file named "olcfg.exe".
Try to change display driver. If this will not help please try to change settings in NGlide config file- nglide_config.exe."
I went straight for step number 7 and that did the trick.