Diagonal-down DOS games you can play online, free in your browser. All 42 titles here start instantly, with nothing to install.
They span 1987 to 1997 and lean towards strategy / tactics, action and role-playing (RPG).
Al-Qadim: The Genie's Curse1994 · Role-playing (RPG)
Amberstar1992 · Role-playing (RPG)
Bedlam 2: Absolute Bedlam1997 · Action
C-Dogs1997 · Action
Cannon Fodder1993 · Action
Castles II: Siege & Conquest1992 · Strategy / tactics
Castles: The Northern Campaign1991 · Strategy / tactics
Command & Conquer1995 · Strategy / tactics5.0
Command & Conquer: Red Alert - Red Dawn1997 · Strategy / tactics
Commander Keen 4: Secret of the Oracle1991 · Action
Commander Keen 5: The Armageddon Machine1991 · Action
Conquest of the New World1996 · Strategy / tactics
Conquest of the New World: Deluxe Edition1996 · Strategy / tactics
Constructor1997 · Simulation5.0
Crusader: No Regret1996 · Action
Crusader: No Remorse1995 · Action
DinoPark Tycoon1993 · Educational
Dungeon Keeper1997 · Strategy / tactics
Fallout1997 · Role-playing (RPG)5.0
FIFA Soccer 971996 · Sports
Ignition1997 · Racing / Driving
Indiana Jones and The Fate of Atlantis: The Action Game1992 · Action
Indiana Jones and the Temple of Doom1988 · Action
King's Quest I: Quest for the Crown (1987)1987 · Adventure
KKND: Krush Kill 'N Destroy1997 · Strategy / tactics
NHL 961995 · Sports
NHL Hockey 951994 · Sports
Roberta Williams' Mixed-Up Mother Goose1991 · Adventure
Sid Meier's Civilization1991 · Strategy / tactics5.0
Skate or Die1988 · Sports
Star Command: Revolution1997 · Strategy / tactics
Star Wars: Rebel Assault1993 · Action
Syndicate Plus1994 · Compilation
Syndicate Wars1996 · Action
The Final Battle1991 · Adventure
The Oregon Trail1990 · Educational
Transport Tycoon Deluxe1995 · Simulation
Ultima VII: Part Two - Serpent Isle + The Silver Seed1993 · Role-playing (RPG)
Ultima VIII: Pagan1994 · Role-playing (RPG)
X-COM: Apocalypse1997 · Strategy / tactics
X-COM: Terror from the Deep1995 · Strategy / tactics
X-COM: UFO Defense1994 · Strategy / tactics