Dino D-Day was originally a Half-Life 2 mod that was later released as a stand alone Multiplayer FPS game on Steam in 2011. The game is set in World War II with a twist: The Nazis have somehow created Dinosaurs that they use to fight the war. Gameplay is similar to Team Fortress 2.
The game eventually received a visual update that added weapons and changed the look of existing weapons. It also added a "Last Stand" mode that's available as DLC.
The M1911A1, called the Colt .45 in-game, is the sidearm for Capt. Jack Hardgrave and Cpl. Joe Spencer. Like most of the weapons it updated the model and fixed a transparent texture that was present in the gun's magazine.
Nagant M1895
Called the Nagant Revolver, it is the sidearm of Ilona Vike. It fires rather slowly, but it is accurate.
Walther P38
The Walther P38 is the sidearm of Camille Brun, the Allied French medic. In-game the name 'Walther' is dropped and it is simply referred to as the 'P38'. Although it may seem odd for an Allied character to carry a weapon most readily identified as a weapon of Germany, Brun's use of the weapon is not inaccurate, as the weapon did see some use by the French. The updated model now allows the slide to lock back when reloading the weapon after it's been emptied.
Luger P08
Olt. Karl Hissman and HptFw. Wolfgang von Graff both carry a Luger P08 (Simply called Luger in-game) as their sidearm. The updated model seems to be a complete redesign, complete with various new animations.
Tokarev TT-33
Released in an update, the Allied sniper Ilona Vike can exchange her Nagant revolver for a Tokarev TT-33 Pistol. Although it deals less damage, it fires much faster than the Nagant, and can also be reloaded substantially quicker (since it uses a magazine).
Rifles
M1 Garand
Jack Hardgrave can carry an M1 Garand as his primary weapon. As with most video game incarnations of this weapon, you can only reload when the weapon's current clip runs dry. The update has made it somewhat smaller.
M1 Carbine
Hardgrave can also carry a M1 Carbine as the primary weapon if the player chooses so. The weapon carries more ammo than the Garand and can reload mid-magazine, but deals less damage to enemy players. Like the Garand, the updated model seems to be smaller.
Mosin Nagant M91/30
The Mosin Nagant appears as the Mosin-Nagant, and has an attached sniper scope. It is the primary weapon of the Allied sniper Ilona Vike.
Karabiner 98k
The Karabiner 98k appears as the Mauser 98k. It is the primary weapon of both Hptm. Kurt Streicher and Hissman. Hissman, being the Axis sniper class, has a scoped variant. Additionally, unlike Streicher, Hissman loads his weapon one bullet at a time, probably due to the scope. Streicher uses a 5-shot stripper clip.
Sturmgewehr 44
The Sturmgewehr 44 appears as the MP-44. It is the primary weapon for von Graff. The updated weapon is mostly the same, with some model tweaks and a far better looking texture. Like many of the visually updated weapons, it appears to have been resized.
SMGs/Machine Guns
M1A1 Thompson
The M1A1 Thompson appears as the Thompson SMG. It is one of two primary weapons for Spencer. The updated model simply provided a cleaner, higher resolution model with better texture quality, and it moved the positioning of Spencer's hands. The size also seems to have been modified, as the weapon appears larger in Spencer's hands, as opposed to before the update.
M3/M3A1 Grease Gun
The Grease Gun is an optional primary weapon for Spencer. It does more damage, but has a slower rate of fire and it is less accurate.
Sten Mk II
The Sten Mk II appears as the Sten Gun and is the primary weapon of Camille Brun. The update gave it a new animations, a darker colored, and less grimy looking texture, and some overall smoother modeling.
BAR
A BAR without a bipod is the primary weapon for Joseph Frank.
MP38
The MP38 appears incorrectly labeled as the MP-40, and is a secondary weapon for Streicher. With a rifle and an SMG at his disposal, Streicher is the only human character to carry what are essentially two primaries. This was most likely done to make up for the fact that the Axis team only has three human classes.
Browning M1919A4
The Browning M1919A4 appears as the .30 Cal MG, and is the weapon attached to the back of the cyber-Protoceratops, Trigger. The weapon cannot be reloaded but can overheat. If it fully overheats, the M1919A4 must cool down completely before being used again. Once ammo runs dry, Trigger must find ammo on the ground or resupply back at the base.
MG34
The MG34 appears in the game as the weapon that is mounted on the back of the Axis Stygimoloch, which serves as their answer to Trigger.
MG42
MG42s appear as mounted weapons near Allied spawn points on some maps, despite being an Axis-issued machine gun. It has unlimited ammo but can overheat like the Browning and MG34. The Axis "superclass," a massive Tyrannosaurus, also carries a pair of MG42s on its head.
Shotguns
Winchester Model 1897 Trench Gun
The Winchester Model 1897 "Trench Gun" appears as the Trench Gun. It has the slowest reload of all the weapons players can use. It is the primary weapon for Blithe-Crossley.
Flechette Gun
Joseph Frank's sidearm is a weapon referred to as the Flechette Gun. It is a single-shot weapon that appears to be a cut down single-barreled shotgun. The crude weapon seems to have only two small straps holding the barrel and the furniture together.
Rocket Launchers/Explosives
PIAT
One of two secondary weapons for Blythe-Crossley, the PIAT is the game's rocket launcher. The updated model has a better form to it, better textures, and operates differently. On the old model, the PIAT was mostly out of the screen, and to fire it the player would have Blythe-Crossley flip up the sight and walk slower in order to aim the weapon. The new model removes this feature, so the PIAT can be fired while moving at any speed.
Mk 2 Hand Grenade
The Mk 2 hand grenade appears as the Mk 2 Frag Grenade, and is used by both Hardgrave and Frank as explosives. The updated model is slightly smaller.
Sticky Bomb
Spencer carries a sticky bomb, which seems to be a fuse activated explosive wrapped in a tar-soaked sock. He lights the fuse with a zippo lighter, and sends it on its way, where it can stick to walls and other surfaces. It can't stick to other players, however. The updated model is mostly the same, but with a better texture, and, like with most of the new explosives, is smaller in size.
Model 43 Stielhandgranate
The Model 43 Stielhandgranate, with a fragmentation sleeve, appears as the Stick Grenade, and is used by both Hissman and Streicher. Model 43s are also used by the Axis Compsognathus (Or compy for short) class, who wears one on their back. Acting as a suicide bomber, the compy's grenade will become more potent as the player kills enemy players through normal methods, such as using their claws. The updated model brings the model quality up as well as the texture quality.
M18 Smoke Grenade
Instead of a hand grenade like Hardgrave and Spencer, Blythe-Crossley is given an M18 Smoke Grenade.
Other
M2 Flamethrower
The M2 Flamethrower appears as the Flamethrower, and is the second option players can choose to use for Blithe-Crossley's secondary weapon.
20mm Gun
The weapon emplaced on the back of the Axis Desmatosuchus.
Non-Firearms
These weapons are not firearms, but are the other three weapons used throughout the game.
Jack Rabbit
Vike can dispense dead Jack Rabbits to distract Velociraptors and Microraptors. She can kill them while they're eating, while the other player looks on in shock and anger as his dino is gunned down in front of him. However, an achievement can be earned if the player controlling a Raptor both eats the rabbit and kills the Vike who dispensed it in one life.
Fists
All allied characters minus Trigger can use their Fists as a backup weapon. Hardgrave's fist has a damage/kill fill-bar for his pair of hands. When the bar fills up completely, based on how much damage or how many kills Hardgrave has dished with his bare hands, Hardgrave turns into the Doom marine and becomes a berserker packing man-and-a-half, being granted with super speed and the ability to kill enemies with a single punch. In addition, his hands glow blue. The effect only lasts a few seconds, however.
Knife
German Human classes use knives as a backup weapon. If they can get behind an enemy Human class, the knife can perform an instantly fatal backstab kill, not unlike Team Fortress 2's Spy character's knife.