The Vindicator is a Siege Tank. Functionally a massively bulked-up Rhino Transport whose transport capacity has been omitted for ammunition storage, extra armor, and a formidable main weapon - a Demolisher Cannon - the Vindicator is a close-range powerhouse, the epitome of the Self Propelled Gun. When it comes to breaking through the reinforced walls of a citadel, destroying squads with a single devastating explosion, or blasting foes out of cover, the Vindicator is brutally uncompromising. Just about every Space Marines army (Loyalist and Otherwise) can find a use for the damned thing, and any sane player fears this thing's ability to devastate anything from a tank to a line of infantry in a single high-explosive-packed rocket.
Like most of the Imperial vehicles from the earlier days of 40k the Vindicator takes its inspiration from an existing vehicle, in this case the WW2 German Sturmtiger, a self-propelled assault gun that sported a massive 380mm rocket-propelled mortar to blast buildings, bunkers and generally anything the enemy could take cover in to smithereens. Could also be based on the Brummbär, which was much less of a failure, very similar, and did the job just as well. See those little holes around the gun's muzzle? Those are gas vents for the rocket's exhaust. The damn thing is so huge the gasses have to be vented while it is being fired or the pressure would rip the gun (and the tank) apart.
The Vindicator is one of those vehicles that doesn't seem terribly good until you actually see it in action. To many newer players, the Vindicator is extremely deceptive; its short range (24" - same range as a Bolter or Lasgun) means it fires infrequently compared to more conventional tanks, its armor on everything except its front is meager, and its "A Rhino With a Gun" appearance tends to draw people into a sense of security. In truth, however, it's potentially the most threatening vehicle on the battlefield if used correctly; one single shell from it can completely change the outcome of a given mission by turning a high-value target or squad into a crater. In general, the Demolisher Cannon the Vindicator fires - a Strength 10, AP2 Ordnance Large Blast weapon - will come remarkably close to earning the Vindicator's points cost back with one shot. If it can survive to fire off multiple shells, the amount of punishment it can crank out far exceeds many other vehicles of its points-cost. e.g. oh, look is that a squad of Honour guard including a captain? *BLAM* No. Terminator armour? *BLAM* No.
Perhaps best of all, 7th edition vehicle rules buffed it. Glancing hits no longer cause Crew Shaken/Stunned. While experienced enemies could stunlock your poor Vindicator in 5th edition and keep it from ever firing a single shot for the whole game, 7th edition Vindicators can actually get a shot of its own off. And anything that tries to trade hits with a Vindicator is going to end up dead in very short order (at least until the Vindicator runs out of Hull Points). Furthermore, with no more halving strength on partials against vehicles, Vindicators now can demolish multiple tightly-packed vehicles in one shot, so even a deployment of this tank can discourage certain armies from building tank walls to mess with your LoS and pathing.
Inexpensive, powerful, and incredibly dangerous to ignore, its main drawback is that it's a colossal fire-magnet and that enemies experienced with them will devote enormous amounts of firepower to the Vindicator's removal, or spend the entire game doing their damnedest to get the fuck away from the things. Its fragile side and back armor means that it usually is fairly easily disabled and/or destroyed if outflanked, though the Repair rule can somewhat mitigate cases of the latter. The Blood Angels Vindicator is a Fast Tank.
It no longer has a good chance of exploding vehicles with a single shot in 7th, so it actually trades poorly with predators and other dedicated anti-tank tanks. Also, 7th Edition allows pre-measuring, so you can measure where the optimal spot to place each large blast is without having to worry if it's out of range.
As of 8th edition, the Vindicator is... meh. The disappearance of templates really hurt it. The Demolisher Cannon now has 1d3 attacks (1d6 against larger units), that must hit, wound and deal 1d6 damage individually. Lucky rolls will allow you to put the hurt on something, but it too random to be reliable, and the Vindicator is outclassed by other units at tank-busting/heavy infantry-shifting.
On the other hand there is a nifty stratagem for both chaos and loyalest marines that lets you drop, a what is effectively, a six inch template if you have three of the things together. This template lets you roll a d6 per unit effected, and on a four up drops 3d3 mortal wounds on them with a plus one to the role for big model count units and a minus one for characters. This can spell one really bad day for a big infantry blob that's hiding something *cough* *cough* AM command squad *cough* *cough* ork bubble meks. The downside to using this is that it will cost you over 400 points and an upwards of 170 dollars cash to pull off this stratagem. Most players usually won't have three Vindicators for their army. (The Linebreaker Bombardment strat and killshot strat were removed in 2019, along with other 3 model stratagems. But the Vindicator has 1d6 shots now)
Come 9th edition, and the Vindicator benefits from the new vehicle rules and the addition of the "Blast" keyword. It can now fire while engaged, although it cannot fire the big gun against any unit engaged with it, and that D6 shots becomes a minimum of 3 against any unit with 6 or more models, and 6 against any unit with 11 or more. It's still not up to the strength of its glory days, but it can still put out some serious hurt.
Vindicators are used by both the Loyalist and Traitor Marines, seeing more use with the latter due to the Chaos Marines' version being a hell of a lot better for the faction fielding it. In addition to obvious upgrades, like Extra Armor, the Chaos Vindicator can pack a Combi-Weapon (Bolter, plus a one-shot secondary weapon, useful for that initial rush into combat), can mount a Dirge Caster (no Overwatch within six inches), and most notably, a Havoc Launcher, which lets the Vindicator fire off a long-range weapon for when it can't move into close-combat. The king of upgrades for it, by and large, however, is Daemonic Possession, which eliminates Crew Stunned and Crew Shaken results on a two up, but reduces the Vindicator's BS to 3. Any Vindicator with this upgrade is virtually guaranteed to last long enough to get a shot off, and it's not as if you care if a template that large scatters two inches anyway.
Deimos Pattern Vindicator Tank Destroyer
One day some Space Marines saw the Imperial Guard shooting rapier laser destroyers out of Chimeras, and got mad that they couldn’t do that party trick with their no-bulky-allowed Rhinos. So they sat down, had a beer (the Space Wolf representative brought enough Fenrisian ale for everybody), and thought: “We can’t put the rapier in a metal box so…let’s just take the gun and mount it ON a metal box!” “And give it MOAR POWAH!” shouted a techmarine from the other end of the table. And thus the Vindicator Tank Destroyer was born.
Unfortunately, 10 thousand years of misplacing the url files of the Vindicator Tank Destroyer's schematics mean that not a lot of these guys are made nowadays. Whilst fairing better than other Imperial vehicles of its era, cost upkeep in terms of its maintenance kind of made this bad boy an uncommon sight nowadays. Only fielded under the most intense and murderfuckingtastic of battlefields.
Unlike the rapier’s 36” range and AP2, the Tank Destroyer’s Laser Destroyer Array has 48” range and AP1. On top of that, if the tank doesn’t move it becomes Ordnance 2, and can choose to overcharge to Ordnance 3, at the cost of a pseudo Gets Hot.
The Vindicator Tank Destroyer can also be taken by Chaos Space Marines too. Daemonically possessed laser destroyer? Yes, please.