Below the Root (Multi, 1984)​
Journey to the Centre of the Earth (C64, 1984) - WIP

 

Pitfall II (Multi, 1984) - WIP​​
​Impossible Mission (C64, 1984/SMS, 1990) - WIP​
Montezuma's Revenge (Multi, 1984) & Panama Joe (Spectrum, 1984)

Underwurlde (Spectrum, 1984) - WIP

Run For It (AII/Atari 8-bit, 1984?) - WIP​
Alchemist (Spectrum, 1984) - WIP​

Volcano Hunter (TSR-80)?
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Bruce Lee (C64 etc., 1984)

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Outliers:

Pyjamarama (PCs, 1984)
Conan: Hall of Volta (Multi, 1984) - Maze Platformer/Puzzle Platformer

Jet Set Willy (Spectrum, 1984/Atari, 1986) - Multi-Screen Maze Platformer/Collectathon (83 items), Avoid enemies/hazards gameplay

Ghost Chaser (Atari 8-bit, 1984) - Maze Platformer, Flip Screen/Multi-Screen

Quo Vadis (C64, 1984)? - Maze Platformer

Sorcery (C64/Multi, 1984) - Maze Platformer (Flight-based, can't jump?)/Proto-PA?
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Grand Larceny (C64, 1984)? - Quest Adventure/Action Hybrid, Side view gameplay, type in commands to interact with the world (24 verbs)

Spirit of the Stones (C64, 1984) - Proto-Action Adventure/Platform Adventure, TD view (overworld)/Side view (houses/dungeons) hybrid, Collectathon

Maxwell Manor (PCs, 1984) - Proto-Action Adventure/Platform Adventure, TD view/Side view hybrid, Collectathon?

Skool Daze (Spectrum, 1984/C64, 1985) - Action Adventure/Puzzle, Side view gameplay w/ minor 2.5D elements (stairs and chairs), Collectathon (pieces of the code to the safe), No platforming