Modular Combat is a role-playing shooter based in the Half-Life universe. There are over 50 modules that can be upgraded at any level, in any combination. Modules give combatants amazing abilities such as flying, teleporting, spawning minions, and shooting flechettes or energy balls.
This mod is good and easy to install (excluding the use of GCFScape) , although it was abandoned, it is still great and I wish it was kept alive, but life intervened i guess.