Base Defense

Base Defense is a co-op modification for Half-Life based on horde-style and RPG systems. You're able to choose one of three classes, then join the fight against most dangerous monsters which are hunting you. Every class has its own abilities and traits. You can become a killing machine or a strong support for your teammates. In game you can get different items with magic powers: helmets, armor and trinkets. As you kill monsters you will get experience points and level ups. Difficulty of the game grows exponentially as you progress, don't forget to upgrade your stats. There are checkpoints every 10 waves, so you won't lose your character and loot.

The war between good and evil was interrupted by an alien invasion. The Demons ran back to hell and the Angels fled to heaven. Only the humans were left, surrounded by aliens. Three heroes called the Defenders send the humans back in time into another realm causing past and present to merge. In-game events are happening after the merging of times.