Does Gallipoli Have Single Player, a Campaign or Bots?
Checked against launch materials:
What Gallipoli actually is
Expedition Mode is a 25-versus-25 fight over objectives and sectors, themed on the expeditionary warfare of the Ottoman Fronts and built around maintaining momentum. Objectives are semi-randomised, so each run through a map differs from the last. That is the whole game: there is no story mode, no horde mode, no co-op-versus-AI variant.
This is consistent with the rest of the WW1 Game Series. Verdun, Tannenberg and Isonzo were all multiplayer-first, and BlackMill has never shipped a narrative campaign in the series. Buying Gallipoli expecting one is the single most common mistake in the store discussions.
Why people keep asking
Two reasons, and they are worth separating. The first is the name: the Gallipoli campaign is one of the most heavily dramatised episodes of the First World War, so people arrive expecting something closer to Peter Weir's 1981 film than to a 50-player shooter. The second is the trailers, which are cinematic enough to read as campaign footage — the landings at Anzac Cove and V Beach genuinely do play out as scripted-looking set pieces, but they are the opening minutes of a multiplayer match, not a mission.
Is it playable solo?
Yes, in the sense that you can queue alone and be dropped into a squad — you do not need friends to press play. But Gallipoli is built so that acting alone is punished. Several classes exist only to support other players: the Ammo Bearer, Stretcher Bearer and Heavy Machine Gunner all double as squad spawn points, and squad type determines what your Officer can call in. BlackMill's own framing is that nothing prevents you from going off to do your own thing, but staying with your squad and playing to its strengths gives you an edge over an enemy who does not.
If you queue solo, the fastest way to enjoy it is to pick a support class and stay within sight of your squad's beacon. You will contribute more, die less, and see the mode work the way it was designed to.
What to play instead if you want a WW1 campaign
Nothing in this series will scratch that itch — Verdun, Tannenberg and Isonzo are all multiplayer. If a 25-versus-25 objective shooter is what you are after, though, Isonzo is the closest comparison and the one worth reading about before buying either. See how Gallipoli compares to Isonzo, Verdun and Tannenberg for the mechanical differences, and the review for whether the launch state justifies the price.