difference between half-life and source
Other than that, not much difference. I'd still recommend using Source when you want to play. HALF-LIFE: Source is the same game as the original HALF-LIFE but it's graphics and physic engine is improved with the Source engine that is used in the HALF-LIFE 2. It is an improved version with better quality. If you want a Source experience choose it, but if you want to remember the old days, buy the original game.