I've shown you mostly cut scenes though, not gameplay. I posted only one gameplay video and that was to show Dante's teleporting abilities because there was no cut scene which showed them.
Anyways, Dante's Devil Trigger works proportional to the weapon he's using. The more powerful the weapon, the more powerful the Trigger. That's why it's called a Devil Trigger and the weapons are called Devil Arms. Also, if you give Dante every weapon he's accumulated, Alucard loses and loses badly. All Dante would need is the Sword of Sparda and it's over. Of course he could use Cerberus to freeze Alucard. Pandora is a briefcase of 666 different weapons. That's only three items from his equipment. I'd rethink that statement were I you. Here's all of Dante's weapons:
Devil Arms
Sword of Sparda
Appearance: Devil May Cry, Devil May Cry 2 (Trish), Devil May Cry 3 (as the Force Edge), Devil May Cry 4, Devil May Cry: The Animated Series, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3
Element: Demon
Form: Longsword (Force Edge), Scythe, sword and spear (Sparda)
Description: The legendary sword of the Dark Knight Sparda, containing the bulk of his devilish powers. It is the goal of Vergil and Arkham in Devil May Cry 3, is awakened by Dante in Devil May Cry, is seen with Sparda in a flashback in The Animated Series, and is taken by Trish and used by Sanctus in the final battle in Devil May Cry 4. Vergil also used its unawakened form in battle with Dante at the end of Devil May Cry 3, and as one of his weapons during his gameplay in Special Edition.
Yamato
Appearance: Devil May Cry, Devil May Cry 3, Devil May Cry 4, DmC: Devil May Cry, Ultimate Marvel vs. Capcom 3, Project X Zone 2
Element: Dark
Form: Tachi
Description: The trademark katana belonging to Vergil as an heirloom from his father, and later coming in to the possession of Nero, and at one point Dante. It is able to cut through nearly anything effortlessly, including space itself.
Rebellion
Appearance: Devil May Cry 2, Devil May Cry 3, Devil May Cry 4, Devil May Cry: The Animated Series, DmC: Devil May Cry, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3, Project X Zone, Project X Zone 2
Element: Magic
Form: Claymore
Description: The trademark claymore belonging to Dante as an heirloom from his father. It is a key element in releasing Dante's devil half, though it must first be awakened by the taste of his blood.
Alastor
Appearance: Devil May Cry, Viewtiful Joe, Viewtiful Joe: Red Hot Rumble
Element: Lightning
Form: Broadsword
Description: The sword manifestation of Alastor the Thunder Devil. Dante finds it impaled through a sculpture of a woman. It is capable of attacking with lightning speed, and allows Dante to perform Air Raid.
Ifrit
Appearance: Devil May Cry
Element: Fire
Form: Gauntlets
Description: The gauntlet manifestation of Ifrit the Fire Devil. Dante finds it resting on an altar in the Colosseum. It is capable of attacking with infernal hellfire.
Cerberus
Appearance: Devil May Cry 3, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3
Element: Ice
Form: Nunchaku
Description: A tripartite nunchaku originating from Cerberus the Ice Guardian. Dante obtains it after defeating Cerberus, the guardian of Temen-ni-gru's gate.
Agni & Rudra
Appearance: Devil May Cry 3, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3
Element: Fire and Wind
Form: Scimitars
Description: A pair of living scimitars, wielded by demonic golems, better known as Agni & Rudra the Firestorm, the guardians of Temen-ni-gru's upper portion. They have rather accommodating personalities, and can be temporarily combined into a double-sided scimitar.
Nevan
Appearance: Devil May Cry 3, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3, Project X Zone, Project X Zone 2
Element: Lightning
Form: Guitar
Description: A weapon capable of transforming into guitar/scythe variants originating from Nevan the Lightning Witch. Dante obtains it after defeating Nevan. It is capable of summoning Nevan's bats to attack, and allows Dante to perform Air Raid.
Beowulf
Appearance: Devil May Cry 3, Devil May Cry 4: Special Edition, Ultimate Marvel vs. Capcom 3
Element: Light
Form: Gauntlets and Greaves
Description: A set of gauntlets and greaves originating from Beowulf the Lightbeast. Vergil obtains them after killing Beowulf and Dante finds them after Arkham activates the Temen-ni-gru and Vergil falls into an abyss.
Gilgamesh
Appearance: Devil May Cry 4
Element: Metal
Form: Gauntlets, Greaves, Mask, and Back Armor
Description: A set of gauntlets, greaves, mask, and back armor made of a living, organic sharped metal equipped with thruster-like machines built inside.
Lucifer
Appearance: Devil May Cry 4
Element: Dark
Form: Backpack, Short Spears
Description: An armor-like apparatus capable of summoning spectral blades very similar to Vergil's Summoned Swords.
Firearms
Ebony & Ivory
Appearance: Devil May Cry, Devil May Cry 2, Devil May Cry 3, Devil May Cry 4,, Devil May Cry: The Animated Series, DmC: Devil May Cry, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3, Project X Zone, Project X Zone 2
Form: Dual customized M1911 pistols
Description: A pair of black and white trademark handguns customized for Dante under the name "Tony Redgrave."
Summoned Swords
Appearance: Devil May Cry, Devil May Cry 3, Devil May Cry 4, DmC: Devil May Cry, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3, Project X Zone 2
Form: Spectral form of the Force Edge (Vergil), Ninja Daggers (Nero)
Description: Magical blades used by Vergil, and later by Nero when in Devil Trigger, for long range attacks.
Luce & Ombra
Appearance: Devil May Cry (Legendary Dark Knight), Devil May Cry 2 (Trish), Devil May Cry 4 (Trish), Devil May Cry: The Animated Series
Form: Dual customized M1911 pistols
Description: A pair of handguns once used by Sparda.
Kalina Ann
Appearance: Devil May Cry 3, Devil May Cry 4, Devil May Cry: The Animated Series, Marvel vs. Capcom 3, Ultimate Marvel vs. Capcom 3, Project X Zone, Project X Zone 2
Form: Bazooka rocket launcher with bayonet
Description: A combination bazooka/bayonet belonging to Lady, but temporarily lent to Dante. It can only be fired while on the ground, and possesses a strong recoil, but can fire multiple missiles and can shoot its bayonet as a grappling hook.
Shotgun
Appearance: Devil May Cry, Devil May Cry 2, Devil May Cry 3, Devil May Cry 4
Form: Sawn-off shotgun
Description: A shotgun with greater firepower, but shorter range and longer reload-time than Ebony & Ivory. (A variant of the Shotgun appears in Devil May Cry 4 as the Coyote-A).
Hi powered shot (available charge shot related skills after upgrade)
Grenadegun
Appearance: Devil May Cry
Form: Grenade launcher with under-barrel
Description: A drum-fed grenade launcher.
Needlegun
Appearance: Devil May Cry
Form: Harpoon gun
Description: An aquatic weapon that rapidly fires needles into the enemy.
Nightmare-β
Appearance: Devil May Cry
Form: Demonic laser gun
Description: A demonic fire-arm which fires reflectable lasers powered by Dante's Devil Trigger.
Nightmare-γ
Appearance: Devil May Cry 2
Form: Demonic laser gun
Description: An upgraded form of the Nightmare-β which Trish uses underwater.
Missile Launcher
Appearance: Devil May Cry 2
Form: Missile Launcher
Description: A missile launcher used by Dante.
Submachine Guns
Appearance: Devil May Cry 2
Form: Dual Heckler & Koch l MP5k submachine guns
Description: A pair of weak submachine guns used by Dante.
Artemis
Appearance: Devil May Cry 3
Form: Demonic Laser Gun
Description: A demonic fire-arm which can fire multiple lasers at either one or many targets, as well as into the sky, creating an "Acid Rain" effect.
Spiral
Appearance: Devil May Cry 3
Form: Sniper Rifle
Description: An armor-piercing sniper rifle with a slow reload-time that can only be fired while on the ground. Its rounds can pierce multiple targets and always increase the Style meter.
Coyote-A
Appearance: Devil May Cry 4
Form: Sawn-off shotgun
Description: A shotgun with greater firepower, but shorter range and longer reload-time than Ebony & Ivory (A variation of the Shotgun).
Pandora
Appearance: Devil May Cry 4
Element: Light
Form: Briefcase (initial), can then transform into a bowgun, bazooka, laser cannon, Gatling gun, mobile missile battery, or a bladed boomerang
Description: A demonic briefcase belonging to Dante. It is capable of changing its form to 666 weapons, of which only seven are used in the game. It is acquired after defeating Dagon and features a new gauge called the Disaster Gauge. The gauge fills through use of Pandora's standard forms and is depleted whenever its Gunslinger modes are used.
Even with all of that, though, all Dante needs is Yamato which can cut through space time. Meaning that even if Alucard goes intangible his ass is grass. Yamato coupled with the Devil Trigger means Alucard is done for.