Death Knight
A semi-large monster with a sword and armour suit. 250 Health.
It's melee attack inflicts either 24-36 damage or 20-30 damage; damage is done in increments of 4-6 for each step of the swing.
It can fire a volley of 6 shots, each inflicting 9 damage.
Enforcer
A solder wearing heavier armor and armed with a laser cannon. 80 Health
The laser inflicts 15 damage per shot, and the enforcer usually fires shots in pairs. The attacks are directed only to the current position with no leadahead.
Drops 5 cells when killed.
Fiend
This appears similar in shape to Pinky from Doom, and is generally known for jumping around. 300 Health.
At melee range, it can claw for 11-15 damage, but usually makes leap attacks that inflict 41-50 damage.
Grunt
A basic soldier with a shotgun. 30 health.
Fires it's shotgun, that inflicts upto 16 damage from it's four pellets. Even though it has an instant-hit weapon, it's not too good at keeping track of the player; running will cause shots to be slightly behind the player. It normally fires one shot, but can refire a second one.
Drops 5 shells when killed.
Knight
A monster with a sword and suit of armor. 75 Health.
It can swing it's sword for 12-18 damage, or charge for 20-30 damage; damage is done in increments of 4-6 for each step of the swing.
Ogre
Fat, and makes a distinctive sound when it spots the player. 200 Health.
Occasionally fires a grenade which spashes for 40 damage.
It's melee attack is the chainsaw, which inflicts 35-49 damage; damage is done in increments of 5-7.
Rotfish
A large pirhana, with 25 health. It nibbles for 1-6 damage, spread under the Poisson distribution.
When this monster dies, it blocks the way longer than other monsters. Also, it doesn't gib.
Fishes always feel pain.
Note: Fishes are counted twice in the number of total monsters. As such, there's no need to scour the map for monsters that don't exist.
Scrag
A flying monster with an appearance of a ghost. 80 health.
It fires it's missiles in pairs, each inflicting 9 damage. After firing, it may either move forward, or slide left/right.
Shambler
A large furry creature. 600 Health.
It can swing it's claw for 1-60 damage (average 30), or try a slightly slower overhead smash for 1-120 damage (average 60). It will always attempt a smash if it's at full health.
If you are too far away, it will try throwing a lightning beam, which inflicts 30 damage. This beam is dodged either by being too far away, or by hiding behind an obstacle.
It's thick caraprice and fur make it resistant to damage - it hardly flinches to most attacks, and only takes half damage from rockets, grenades or other explosions (even on a direct hit.) They are easily killed with thunderbolt and the super nailgun, however.
Spawn
Also called a tarbaby, this small blob will jump around once it's alerted. 80 health.
It's main attack is its jump, when it hits (and it's fast enough), it inflicts 11-20 damage.
When killed, it explodes for 120 damage.
Vore
This monster has an appearance of a three-legged spider. 400 Health.
It's missile explodes for 40 damage (but instantly kills a zombie it touches.) However, it's the only projectile that attempts to home in on it's target, changing directions every 0.2 seconds. It takes a direct path, and thus will fly into a wall rather than trying to seek around it.
Zombie
Zombies are dead individuals, that can't seem to die. Can only be killed by gibbing; this required an attack that does 60+ damage (either an explosive, or a quad-enhanced weapon.)
They throw meat at the player, which inflicts 10 damage.
However, you can stun the zombie if you hit them hard enough - either one heavy shot, or a few quick shots in a row.