Marvel Cosmic Invasion: The Siege of Castle Doom (DLC) – Review

Sometimes, a game’s post-launch DLC just makes sense. Tribute Games’ Marvel Cosmic Invasion, the old-school superhero 2D beat-em-up released in December 2025, already featured an impressive roster of Marvel heroes, from the well-known like Captain America and Iron Man to deep cuts like Beta Ray Bill and Cosmic Ghost Rider, but now it’s adding someone familiar and pretty apt to its cast.

Among the most anticipated Marvel Studios movies of 2026 sits the upcoming Avengers: Doomsday, so it’s no surprise that the game is leveraging this hype for its The Siege of Castle Doom DLC, which doesn’t just feature the titular villain as a playable character, but also introduces a brand-new roguelike mode alongside it.

The challenge Marvel Cosmic Invasion faces here is finding a way to draw players back into the game, as while the base game was a pretty decent time with a varied range of unlockable characters and a simple but serviceable brawler system, stage and enemy variety wasn’t its strong point. Which means there weren’t many reasons for players to return after trying out all its missions and characters. 

This DLC aims to address this issue, providing a separate new mode where every “run” is different, and with an unlockable set of modifiers to further switch things up. But at the end of the day, it’s not going to change anyone’s minds if they didn’t already resonate with the main game, and it serves as a fun little diversion for returning players to sink in a couple of extra hours, but not much else.

Like its name suggests, The Siege of Castle Doom DLC centres on players taking on Doctor Doom’s castle of… well, doom. And that’s about it when it comes to any sort of narrative, so don’t go in expecting the same quality of cutscenes seen in the main campaign, but then again, that’s not the point when it comes to roguelike games, as it’s all about how enjoyable and varied each run can get.

Each run takes place at the bottom of three “floors” of Castle Doom that players will need to ascend. Like the main campaign, players can bring two heroes (or villains) into each run and swap between them at will, but that’s where the similarities end. Each assault on Castle Doomstadt operates on managing two main gauges – Filling up Stabilizers and the Siege Gauge.

Presented as two circles on either side of the screen, the objective here is progressing through procedurally generated rooms and picking up Batteries from defeated enemies or the environment, which will slowly charge up the Stabilizer. Upon charging up a Stabilizer, the player will also gain a perk point, which can be spent towards a choice of a run-specific upgrade, such as defence and attack bonuses, with the goal of charging up three Stabilizers per stage to advance to the castle’s next level, with the mode culminating in a showdown with Doctor Doom himself.

On the other hand, the Siege Gauge operates like a clock that is slowly ticking down. Every time a player is hit by an enemy attack, the gauge slowly fills up and can be depleted again by defeating foes, and once filled up, it’s an immediate game over. In addition, every enemy in the run will also get stronger and faster as this gauge increases, meaning the countdown may vary depending on player performance, as all it takes is one careless move for a run to end prematurely.

As a roguelike mode, The Siege of Castle Doom lets players pick and choose how they progress through the game. After clearing rooms, players will usually have a choice of three rooms to enter next, with symbols determining their type. These can range from rooms that give health pickups or a large number of Batteries to event rooms, which feature a randomised objective to complete, like surviving a massive wave of enemies or a rematch with one of the main campaign’s bosses, but these rooms can also be helpful, as they may reduce the Siege Gauge upon completion, among other rewards like pausing the gauge for the next three rooms.

Another new feature of the mode is special item pickups, which can be activated with the RT button. These powerful moves operate on a long cooldown, but can turn the tide of battle, such as a cannon that fires a large black hole in a straight line, or items that enable lifesteal for a set amount of time, with these abilities also being upgradable in specific rooms.

Finally, there are Marvel Cosmic Invasion: The Siege of Castle Doom’s two new playable characters, Doctor Doom and Invisible Woman. In terms of character archetypes, Doom plays out somewhat like a combination of Storm and Beta Ray Bill, focused on dealing big damage but with a slow movement speed. Invisible Woman, on the other hand, is more technical, as although she doesn’t deal a lot of damage, she’s nimble and can even turn invisible while running, meaning she can sneak up behind pesky shielded opponents. 

As a whole, while the DLC introduces some neat new features, it doesn’t change the fact that, like the main campaign, things start to get stale pretty quickly. While players can choose what types of rooms to enter, it’s all themed to the same backdrop as the floor they are on, meaning players are going to see the same library walls, snowy balconies, and slow-moving mechanical lifts as they progress through each run. The big showdown at the end is quite the letdown too, with Doctor Doom relying mostly on summoning minions and deploying easily avoidable traps instead of anything actually interesting.

Speaking of minions, here’s another aspect of the DLC that doesn’t quite hold up. Players will be spending a majority of their time fighting the same kinds of foes seen in the main campaign, with the DLC’s only new addition being Doombots – robot hooded spear-wielding minions that come in three colours, each with their own moveset. Compared to the other main game foes, these new minions don’t pose as much of a threat, as their attacks are very telegraphed and easy to avoid or counter.

Being a roguelike, success in the new mode also boils down to luck of the draw, as enemy spawns can sometimes be extremely annoying and throw multiple shielded enemies at a player at once, or hard-to-hit flying foes. These can really mess up a run, especially when near the final floor, with deaths sometimes feeling unfair depending on which combination of foes the game decides to spawn.

At least a player doesn’t completely lose everything upon defeat, as for each Stabilizer charged during a run, a player will earn one point for use in Reed Richards Laboratory, where they can then unlock modifiers for a run. Most of these are designed to make things harder, however, such as adding traps to rooms, disabling character swapping in exchange for two lives, or buffing every enemy in the game.

Marvel Cosmic Invasion: The Siege of Castle Doom is far more substantial than the game’s previously released character packs, but like many such post-launch content drops, enjoyment entirely depends on how players already feel about the base game. For those who are itching to squeeze out a couple more hours of retro beat-em-up action with a few new toys to play with, its offerings are solid enough to consider a purchase, but for everyone else, this mode isn’t going to make the game any better or worse than it already was.

Kevin Low

Kevin is a reformed PC Master Race gamer with a penchant for franchise “duds” like Darksiders III and Dead Space 3. He has made it his life-long mission to play every single major game release – lest his wallet dies trying.