this game is great.
Half Life 2 Episode 1 does not add much to Half Life 2. Instead of adding new weapons or enemies, it decides to master what was seen in Half Life 2. It simply brought HL2 into a bigger and greater universe. Although most battles are in slim corridors, there are some grander battles. The zombie level in HL2: i think it was called we don't go through ravenholm, has been recycled but was so much funner this time around. In short, Half Life 2 Episode 1 is basically Half Life 2 but improved on dramatically. As far as the length goes, it was perfect, it was a 6 hour game.. and it stayed on focus the entire time, the plot stayed clear, there was no stalling on anything.. and it didn't feel as if valve were recycling much...
anyways, if you have yet to played Half Life 2 Episode 1... do so right now.