Marvel Strike Force has several different game modes, these are listed below in no particular order.
Campaign
This mode is where the main story unfolds. The chapters in this mode costs Campaign Energy to play and can be replayed to farm specific rewards. If you manage to clear a chapter with three stars you will unlock Auto Win which although costs the same amount of Campaign Energy will save you time.
Challenge
This mode is a set of rotating challenges that give you the opportunity to earn Gold, Health Packs, and Training Modules. Each of the challenges can be played three times in its 24-hour period. Once you have cleared a challenge with three stars you will be given the option to Auto Win a Challenge. Challenges will have multiple difficulty levels with better rewards as you move up.
Arena
This mode enables you to battle against the teams of other players. You basically choose your best five characters regardless if they are heroes or villains and then pick one of three possible opponents you can battle. If you win you move up to your opponents rank and if you lose you remain at your current rank. Arena Credits will be sent to your Inbox every 24 hours based on your rank which can be spent at the Arena Store. You are limited to five Arena mode attempts a day.
Events
This mode is a character focused quest that gives you the opportunity to unlock the hero or villain at their centre by playing a series of battles. If you already have the character Events will enable you to raise them to a higher tier. To participate in some Events your character profile will need to be level 20 or above.
Blitz
This feature is basically a secondary PvP mode that enables you to battle teams created by other players. The objective is to earn points to reach milestones that grant you rewards. Blitz mode has its own currency called Blitz Charges which you need to spend in order to keep using the same characters over again. Conversely, you can swop characters into your team.
Alliance Raids
This mode is only available to those players who have joined an Alliance. Raid modes are co-operative quests where you work alongside other players with the common goal of defeating groups of foes and reaching milestones that grant you rewards. Like Events and Blitz mode it also has its own store.