Single Player mode is great on Action Half-Life.  For one, instead of waiting for a weapon lying on the ground, why not knock out of officer after letting you through a section and take his Berreta, though it may only have 1 clip [15 rounds], isn't it better than punching and kicking?  The Single Player mode basically is the Original and Game of the Year edition of Half-Life... but with 100 times more realistic weapons, plus they're better.  It's great to bend down and wait for a zombie to come towards you... the aim upwards and fire with the Shotgun, making it go flying into a wall!  Yes Action Half-Life is great... but why not make it's own levels?  Well, for one it's an early version [Beta 4].  Many say that Beta 4 and Beta 5 are early stages of the game, and the best is to come.  Well, it's probably true.  If you want even more information on this great mod, go to the official site at http://ahl.telefragged.com