Planet Strike, the sequel of the original Blake Stone, adds many interesting tricks which don't make it a totally "new" game, but it's pleasant and less "Wolfenstein-like" than it's precedessor. Those tricks are i.e. weapon bobbing, new map system, one new weapon, traps and bomb, which you must use on the specific object to end each level. Also, there is much more types of mutants, sadly without any new abilities or attacks, and some of them are just boss creatures from original Blake. 20 levels of PS in comparison to 60 of BS isn't overwhelming, but trust me, they won't be a breeze (maybe if you choose the 1st difficulty level, coward). Planet Strike is also harder, looks better (and darker), and overally makes a great addition to collection of "corridor shooters".