2-27-2013: Newest build released! Follow the download links on the right.
Step by step download instructions:
1. Download the game from http://www.metablast.org/downloads from the links on the right side of the page (This page).
2. You should get a zip file in your downloads folder named MetaBlast - Win.zip assuming you're using windows. It contains a file named metablast.exe and 2 folders, one called metablast_data and another called _MACOSX.
3. You need to extract the files from the folder since zips are compressed. You can do this by right clicking on the folder and pressing 'extract all' and target the location you want the folder. You can also use a program like winzip or 7zip to unzip the folder.
4. You should now have an unzipped file folder wherever you choose to extract it to. Navigate into the folder and just double click metablast.exe, that will launch the game.