In half-life,the story is about a scientific experiment to open the portal to an alien universe,however the experiment went wrong and aliens start to appear in their world.The quest for Gordon to kill the Alien King - Ninilith - Once and For all. I do not recommend Half-Life Redemption to be played for beginners.The monsters are all mixed up and the one headed dragon monster appears first in the game but only in chapter 5 - 8 in the Half-Life new game. And the Monarch "the spider monster" who has 4 legs and sprays chemical that does alot of damage,should not be so early released in the game , i only encounter the Monarch in half-life at the end part; chapter - Monarch's Lair , right after Interpolion.Half-Life is a more modern and fun New Game just like redemption but this time with the ceiling dangling monster , the apprehension monster; the fish like monster. But this time , u get to kill the blue shell monster and the Monarch. I completed half-life new game and the ending part features gman complimenting YOU , on how u stopped the reacons and the alien king.

Here are some ways to kill the certain type of monsters:
Big Curved and has a blue body with two hands which emitts flames; Normal Ammo or bullets wouldn't do a single damage. Only Explosions should be used and environmental hazards ; e.g Electrical Currents.

Fish like monster that resides in the water; Do not be afraid of this distinctive monster, Use the Crossbow and shoot it,be it underwater or on land, both is acceptable.

Monarch,monster that resembles a spider,4 legs; Only encounted in XEN and in chapter - Monarch's Lair. Shoot and bomb it until it runs through the hole and becareful , the floor of the hole is slippery! When the Monarch drops into the pit , stay on top , bomb it until u see a slight change in color,then jump down (Drop at the corner , NOT DIRECTLY ABOVE THE MONARCH ) Convince the Monarch; shoot it or bomb it until it goes close to a POINTY SHARP TREE LIKE MONSTER; not active monster,only hits when shot or attacked. When the Monarch is close to the Sharp Thing,Shoot the sharp thing and the monster will be killed.(This attempt may not suceed,multiple tries may be needed.)

Steps to defeat the alien king: The -Ninilith-.
First,There are 5 crystals if u notice around the map,run around shoot down all the crystals and monsters in the map,DO NOT SHOOT OR FOCUS ON THE BOSS. just run around,makes sure the boss does not hit u and shoot the crystals.
Next,When the crystals are down the boss will make a teleport move that will send u to a maximum of 4 places.

The First place;Shoot the flying monsters and jump ur way up.
The Second place;Shoot all monsters and take the small round ball up to the ceiling.
The Third Place;Use ur crossbow and kill all the fishes and monsters.
The Fourth and Final Place: it is the same place as the third. Use explosions kill the monster and jump ur way up to the portal.

Finally,Shoot with all ur ammo at the Ninilith and once the ninilith has no more energy balls around him and his head opens,jump to the top using the weird round thingy on the floor and shoot the triangle thing inside his head.Then he will die and u will be teleported to the ending game where u will find the person who hires u.

Easter-Egg:
At the end game , ur given a choice to choose to be hired or not. Do not go into the portal,just wait to be transferred and u will see alien armies and alien ships hovering around you.