In Deadfall Adventures , the protagonist is an archaeologist adventurer accompanied by a cheeky female sidekick, visiting various places worldwide in search of the artifact Heart of Atlantis. The hero's journey takes him through different locations as he fights against evil Nazis and Russians while on his quest. The story and dialogues are full of tongue-in-cheek moments and B-movie clichés.
The game alternates between action and puzzle-solving sequences. The action part is a typical first-person shooter: James walks around, shoots enemies, and avoids taking damage. In addition to human enemies, there are also mummies that can be weakened by blinding them with a flashlight. Later in the game, environmental traps can be triggered to harm enemies.
The puzzles are mostly of the switch and trigger variety. Examples include solving light beam puzzles or choosing the correct floor tiles to walk on. Allan's old notebook serves as in-game puzzle help, and the separate puzzle difficulty setting controls how much it reveals. By finding hidden treasures, James unlocks the opportunity to buy upgrades like more health or faster reloads.
Multiplayer offers competitive modes such as deathmatch and capture-the-flag, including classes and level unlocks. There is also a co-op surviving mode where players must survive mummy assaults.