Call in. A single player mod which plays out at the same time as Gordon and Alyx flees the citadel in Ep1. You take the role of a rebel soldier on a mission to retrieve information regarding the super portal to aid in the building of Dr. Magnussons rocket.
The pacing and gameplay were spot on, you really thought it out, showing the players the enemies before fighting them really helped make the transition into combat much smoother and overall made the pacing of the levels that much better. This is a very good little campaign, however, in the first level I dies once and when I reloaded the opening music started playing again, not a bad thing, but change the "logic_Auto" entity to play the sounds when the level is loaded, not when the player spawns. Another thing I must say is that wood walls are much thinner than plaster walls, the thickness of the walls made sense in most parts, but the wood walls looked wrong, use real life reference more often in the future. Overall, it's a darn good campaign, and you really got the styles of the HL2 areas down. Good luck with your next project, and one last thing, don't be afraid to use combat music, running with the air boat and fighting heli would have been much better if there was some of the HL2 music going to it.
Oh, and before I forget, tell your testers to try playing on hard, make sure your mod plays with a good challenge level on all difficulties, because I only play on hard, and there were not enough medkits for the amount of enemies in some of the fire fights, and my god, 3 hunters in a close combat situation with barely any firepower!? I was lucky to take out the last guy with the pistol with 20 HP. But, now that I've made this go too long, good luck with your future projects...