Legacy Kollection online play and crossplay

The two modes

Online play in Legacy Kollection runs through two separate systems, and the difference between them matters when you are trying to play with a specific person.

Online play was not present at launch. It was added in the December 2025 Online Arcade update and expanded by the April 2026 Krossplay update, so any description of the collection as a single-player package predates both.

Turning on Krossplay

This is the single most common reason people report that crossplay is not working.

1. Open the game and go to the online section.
2. Open Online Options.
3. Turn Krossplay on.

Once it is enabled, players on PlayStation, Xbox, Switch and PC can be matched together. Digital Eclipse has not published a permanent opt-out for individual platforms, so the setting is the only control.

Online 2v2

Online two-on-two is the narrowest part of the feature set. It covers four games, not the whole collection:

• Ultimate Mortal Kombat 3 — arcade version
• Ultimate Mortal Kombat 3 — SNES version
• Mortal Kombat Trilogy — PlayStation version
• Mortal Kombat 4 — arcade version

If you were hoping to run a 2v2 night in an earlier game, the version you pick is the deciding factor. The rest of the online rotation is one-on-one.

Rooms and lobbies

Online Arcade rooms are the part of the system Digital Eclipse documented most fully, and the rules are specific.

Known limits

Two limitations are documented by the developer rather than inferred, and both affect how you plan a session.

• Not every game goes online. Digital Eclipse’s wording is that the majority of the games support online play. The collection is commonly described online as putting every included title online, which overstates it. The contents page lists what is in the collection.
• Mortal Kombat Trilogy on the original Switch. The PlayStation version of Trilogy does not support online Krossplay on the original Nintendo Switch, which Digital Eclipse attributes to a technical constraint. Switch 2 is not affected.

Two further points come from the developer’s own question-and-answer material rather than from a patch note. Rooms do not give the host a way to remove another player, so a private room with a shared code is the control mechanism rather than a kick option. The visible record is also sparse: the system tracks win streaks rather than keeping a full win-and-loss history for each player.

Because the collection spreads players across many titles, a popular game fills faster than a rarely played one. If a room looks empty, that is usually the cause rather than a connection fault. The input lag page covers the display side if matches feel delayed once you are in them.