(1) First you will need Voodoo 1 drivers. You can download the drivers for the Diamond Monster 3D, from Diamond MM's FTP here: ftp://ftp.diamondmm.com/pub/display/monster/monster3d/m3d1600.exe You must extract the following two files from the drivers and place them into the Mech 2 directory (or whatever your main installation folder is):

glide.dll
sst1init.dll

(2) You need to create a batch file (*.BAT) called "mech2.bat" (or "whatever-name-you-want.bat") in your Mech2 directory. If you're unfamiliar with how to do this, you can just open up a blank text (*.TXT) document in Notepad, then copy and paste the following information into it and save it as to the *.BAT file. It should contain the following lines:

set SST_GRXCLK=90
set SST_FT_CLK_DEL=0x4
set SST_TF0_CLK_DEL=0x6
set SST_TF1_CLK_DEL=0x6
set SST_VIN_CLKDEL=0x1
set SST_TMUMEM_SIZE=2
set SSTV2_FASTMEM=1
set SSTV2_FASTPCIRD=1
set FX_GLIDE_ALLOC_COLOR=3
mech2.exe

(3) Double-click on the *.BAT file you created to start the game. You can also create a shortcut to the *.BAT file you created and give it an icon if you wish. You might want to go into the shortcut's properties and put a check into the "Close on Exit" box on the Program Tab, so when you play you won't have to close the box that the batch file creates everytime you play.

Explanation: The problem is due to the game using an early version of the glide.dll (one that is lower than 2.1), that predates and is not supported by Voodoo 2 cards. The combination of variables in the batch file makes the game think it's running on a Voodoo 1 card.