Overview

Short answer: Largely unexpected. The ANZAC soldiers and their commanders hoped for a quick, limited operation, but they encountered fierce resistance, terrible terrain, supply and medical problems, and a long, deadly stalemate. Some practical difficulties were foreseeable, but the scale and nature of the disaster surprised most people.

Step-by-step explanation

1. What the Allies expected before the landings

   • The plan (led by Britain) aimed to force the Dardanelles, capture Constantinople, and knock the Ottoman Empire out of the war. Many thought it would be a fast, decisive move.
   • Commanders believed they could land troops on beaches, seize the nearby heights, and rapidly open the straits. There was optimism that Ottoman forces were weak or disorganized.
   • On the soldiers' side, many ANZACs expected tough fighting but a clear advance after landing — not prolonged trench warfare.

2. What actually happened when ANZACs landed (the unexpected shocks)

   • The landings on 25 April 1915 faced unexpectedly strong and prepared Ottoman defenses. The Turks held the high ground, which made advancing from the beaches very difficult.
   • Terrain was far worse than maps or planners had suggested: steep ridges, narrow gullies, and scrub made movement and coordination nearly impossible.
   • Command and communication problems meant units were often confused about objectives. Instead of a quick advance, the ANZACs were confined to narrow beachheads and soon dug in.
   • Casualties were heavy. Many soldiers and communities were shocked by how many were killed or wounded in a campaign that had been expected to be short.

3. How the campaign developed — more surprises

   • Instead of a rapid victory, the campaign turned into months of trench warfare similar to the Western Front. This was not what most Anzacs or planners had predicted.
   • Logistics and medical evacuation were inadequate: wounded could not be moved quickly, and disease (like dysentery) spread in the crowded, unsanitary conditions.
   • Allied naval efforts also failed to force the straits, which many had hoped would help the landings succeed. The campaign became a costly stalemate.
   • The eventual evacuation in December 1915–January 1916 was surprisingly well-executed and relatively low in casualties — that success was unexpected given earlier mistakes.

4. What was foreseeable or predictable?

   • Some general problems were predictable: amphibious landings are hard; moving and supplying troops over a beachhead is difficult; strong defensive positions on high ground are dangerous to attack.
   • Critics had warned about the risks of the plan and the need for better intelligence and preparation. In that sense, planners should have expected many challenges.
   • However, the specific combination of poor planning, underestimation of Ottoman capability (including effective leadership by commanders like Mustafa Kemal), and the harsh detail of the terrain were not fully anticipated.

Key reasons the ANZAC experience was mostly unexpected

• Underestimation of Ottoman forces: The Turks fought effectively and were well-led and motivated.
• Poor intelligence and planning: Commanders lacked accurate maps and clear plans for the terrain and objectives.
• Terrain and geography: Beaches led immediately to steep ridges and defensive positions, turning the situation into trench warfare.
• Logistics, medical and communications failures: Supplies, reinforcements and wounded evacuation were often mismanaged.
• High casualty rates and prolonged stalemate: The campaign lasted months and cost thousands of lives — far worse than many expected at the start.

Balanced judgement

Conclusion: While certain practical difficulties of an amphibious operation could have been predicted, the ANZACs and the Allied planners were largely surprised by how effectively the Ottoman forces resisted, how poor planning and bad terrain trapped the troops, and how quickly the operation turned into a costly and prolonged stalemate. So, the ANZAC experience at Gallipoli was unexpectedly severe in scale and consequence, though not entirely without warning.

Quick essay plan (useful if you need to write about this)

1. Introduction: give short context (Gallipoli 1915, ANZAC landings) and state your judgement (e.g., largely unexpected, with some foreseeable issues).
2. Paragraph 1: Allied expectations and reasons for optimism (naval plan, hope for quick victory).
3. Paragraph 2: Immediate surprises at the landing (strong Ottoman defense, terrain, confusion).
4. Paragraph 3: Longer-term unexpected problems (trench warfare, disease, logistics, high casualties).
5. Paragraph 4: What was predictable (risks of amphibious operations, criticisms ignored) and limitations to the claim that everything was unexpected.
6. Conclusion: restate judgement and summarise main points.

If you want, I can help you write a full 5-paragraph essay using this plan and include specific evidence and quotes you could use.