However it should be noted that the $5.99 price will not be a permanent one as this is actually a promotion where the developers will be knocking off 25% from its original price of $7.99. This offer will be valid until the 7th of February, which might clue us in to when the game will be released, although this has yet to be confirmed. The Steam version of Metal Slug 3 will come with full controller support which is great for those who want to play it old school style. It will also suppose Steam’s Big Picture mode, achievements, and leaderboards. While the game will be compatible with Windows-based operating systems, it will not be compatible with Windows XP.