The Shadow Over Innsmouth

It has beautiful models and mapping, though there's a lot of errors.

2nd mod I've beaten.

Comatose (Part 1)

A good mod. There isn't much to say about it because it's so short at the moment.

-To Be Continued-

Black Mesa (Part 1)

So far what they have presented to the public is an absolutely beautiful and solid mod. Currently Black Mesa  goes up to right before you enter Xen (the alien world, also known as the border world). I highly recommend this mod if you're an old fan of Half-Life 1 or a new person to Half-Life 1 or 2.

-To Be Continued-

Underhell (Part 1)

The House (kinda like the menu) is the scariest part and is pretty interesting. The actual Prologue was fun, and went out in an epic ending - or rather beginning.

-To Be Continued-

Nightmare House 2

Probably the funnest horror game I've played, next to Doom (which isn't a mod). The ending was epic. You'd love it if you liked games like FEAR and Doom 3.

1st mod I've beaten.