Marvel Cosmic Invasion was a bit of a dream game for me; I loved the X-Men arcade game in the ’90s, so when Tribute Games released the excellent Teenage Mutant Ninja Turtles: Shredder’s Revenge in 2022, I immediately hoped they’d revitalize other licensed brawler franchises released by Konami in the late ’80s and early ’90s. While we still haven’t heard any word of a new brawler starring The Simpsons, Tribute did follow up its Turtle triumph with Marvel Cosmic Invasion, another throwback side-scrolling beat ’em up, this time starring Marvel’s mightiest.
I played through Marvel Cosmic Invasion multiple times and had a blast, but I moved on quickly, as I didn’t feel the need to collect different palette-swaps of the many heroes on offer. Even after Cyclops and The Thing joined the roster as DLC in May, I still saw Cosmic Invasion as a game in the rearview. That changes this week, as The Siege of Castle Doom not only adds two additional playable characters (Invisible Woman and Doctor Doom), but also a mode that has the potential to bring me back for more runs for the foreseeable future.
Seeing that Annihilus is threatening the universe, Doom decides to take matters into his own hands. Unfortunately, much in the way that it seems that he may try to fix the multiversal incursions in the upcoming Avengers: Doomsday, Victor Von Doom’s solution in Marvel Cosmic Invasion – the Cosmic Inductor – would lead to untold death and destruction. In The Siege of Castle Doom, you select your team and fight your way through various floors of the stronghold belonging to the man who is perhaps Marvel’s greatest villain. Your goal is to fight through the winding, randomized hallways of Castle Doomstadt, charging Reed Richards’ Stabilizer and tactically bolstering your team along the way, before Doctor Doom can enact his plan.
As for the new playable characters, Doctor Doom is less agile, but his attacks pack a whallop, while Invisible Woman’s force fields and speed make her the more versatile pick. I don’t know that I see either of them replacing my mains from the base game, but I had fun experimenting with them throughout this mode. Regardless of which character you choose from the expanding roster, you still must traverse Castle Doomstadt before Doom achieves his objective.

Fighting through waves of enemies across differently themed and booby-trapped rooms, you encounter all manner of foes from the base game, as well as new minion types from Doom. When you defeat enemies, they drop batteries that charge your Stabilizer, letting you even the odds and stop Doom. Conversely, each time an enemy hits your character, it charges Doom’s Cosmic Inductor, inching him closer to victory and making his minions faster and stronger in the process. As you might expect, the rooms get harder the deeper you go, and while each player starts with two characters to swap between, if a character completely depletes their health, they’re gone for good, making it even tougher. As such, you need to keep your eyes on each character’s health and swap them out when it makes sense.
As you complete each room, you can choose which path to take to augment your characters with new special abilities. True to the roguelite structure, as you complete rooms, you can also buff your characters’ stats within the run. Certain rooms offer extra batteries to help your Stabilizer charge, while others offer new and upgraded equipment. There’s also one that promises random events that can easily alter the trajectory of your run for better or worse. Though I often enjoyed boosting attack stats to make enemies less like damage sponges, I had to balance that against buffing their health to keep them alive and charging the Stabilizer to have a fighting chance.
Beyond the in-run upgrades and modifiers, you can also amp up the action run-over-run through upgrades in Reed’s Lab, which add to the pool of modifiers you can select from at the start of each run. The expansion also adds new palettes for existing heroes, plus new music by composer Tee Lopes. While I’ve only done a few runs of The Siege of Castle Doom (each taking between 45 and 90 minutes, depending on how successful you are), I feel a revitalized sense of excitement for Marvel Cosmic Invasion. Tribute claims completionists can spend upwards of 15 hours in this new mode, which has me champing at the bit to dive back into what will likely be my primary way of interacting with Marvel Cosmic Invasion going forward.
Marvel Cosmic Invasion – The Siege of Castle Doom is available today on all platforms, and it is a strong addition to an already great game. You can read our review of the base version of Marvel Cosmic Invasion here.

