Yostar Limited's popular tower defence game Arknights continues to roll out regular updates to keep fan interest in the game, which seems to be working given the 1 million-plus downloads the game has on Google Play alone. The latest update and event is called Contingency Contract.

These will be a series of highly customisable challenge stages that are designed to test the flexibility of player's squads. So depending on the level you're at currently in the game you'll be able to tailor this event for your difficulty, with long-time players being pushed more so than in prior events.

There are three main operations players will take part in, each with its own set of enemies and mission rewards. Chernobog Operation will be constant throughout the event while the other two Lungmen Outskirts maps will rotate through different Operations during the day.

There will be both daily objectives, called Emergency Missions and Long-Term Missions. By completing these players will be able to collect Contract Bounties which can be exchanged for free event resources alongside Operation Agreements which are used for unlocking more Contingencies. Players will also be able to get Siege's new outfit 'Legacy' as a free reward from the Secret Sanctuary Shop.

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The Contingency Contracts themselves will impart various restrictions on player's characters that will make defeating enemies more difficult but increase the rewards they'll receive. Meanwhile, there will also be Support Contracts available that will help players complete and earn various event rewards.

Different combinations of these contracts will allow players to effectively play the game with almost an entirely different ruleset. The buffs on offer from the Support Contracts and even some of the restrictions will allow players to try out tactics that may not have worked previously.

Arknights is available now over on the App Store and Google Play. It's a free-to-play game with in-app purchases.

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