Co-op in Project Rabbit was not added to a finished single-player game. The studio describes it as "tactical co-op soulslike" designed from zero for cooperative play, and the two systems that prove it are unusually specific.
This is the headline co-op feature. The dual skill system allows two players to combine their abilities — one character's skill operating as an extension of the other's rather than as a separate option. What that produces in practice is a temporary, player-specific build that only exists while you are paired, and which you cannot replicate solo.
The tactical consequence is that co-op partners are not interchangeable. Two players with the same weapon and similar skill trees can still run entirely different encounters because their combined skill configuration is different. The developers have said as much: the game was built to be about coordination rather than about bringing more damage to the same fight.
The exact rules — which skills pair, whether the combination is symmetric, whether a downed partner's skills still count — have not been published. This is the single most interesting system in the game from a design standpoint, and also the one with the least publicly documented behaviour.
A downed teammate can be revived. In the context of a game where death means losing everything, this is a structural feature rather than a courtesy: a revive is the difference between a bad run and a lost run, and it is what turns the extraction loop from a solo gamble into a managed risk.
Note the interaction with the extraction rules, which has been raised in preview coverage. If a player dies and drops their carried items, a revive must work differently from a full restore — reviving a body that has already dropped its inventory would restore the person but not the loot. The studio has not clarified this, and it is one of the more consequential unanswered questions about how co-op actually plays.
The game is announced for PC, PS5 and Xbox Series X|S, and the Steam page carries the cross-platform multiplayer tag. Combined with the PvPvE structure, that implies a single pooled population across all three platforms for both co-op and hostile encounters.
The one platform caveat worth flagging is the Steam Deck: the store page lists Steam achievements and family sharing but there is no compatibility assessment, and the recommended spec calls for an RTX 3070 and 32GB of RAM. Nobody knows yet whether this runs on Deck.
This is the sharpest criticism aimed at the game's design so far, and it deserves stating plainly rather than smoothing over. The combination of multi-phase bosses, permanently losing everything on death, and co-op abilities that only work in a party means the multiplayer path and the solo path are not merely different in difficulty — they are different in kind.
A co-op team facing a phase change can cover each other's recovery windows, split a boss's attention, and combine skills into configurations a solo player cannot reach. A solo player has to absorb all of that alone, with the full penalty for failure. Chinese-language coverage raised this directly as a risk, and English coverage raised a related one: that in a game with perma-loss stakes, "even the smallest mistake can lead to a fatal conclusion" is much harsher when you cannot be revived.
Whether the developers add a solo-friendly difficulty option, a partial-loss rule, or AI companions is not known. It is, however, the most likely area where a balance patch would land first after launch — and the thing to watch in any roadmap update.