Games like Mr Twiddle's Wee Diddy Farm
Games like Mr Twiddle's Wee Diddy Farm include Skul: The Hero Slayer, Vampire Survivors, Hades, Risk of Rain (2013), and War Thunder. We matched them by the tags players give Mr Twiddle's Wee Diddy Farm on Steam (Action Roguelike, Incremental, Action, Perma Death, and Combat): closest matches first, and among equally close ones the better-known games.

Skul: The Hero Slayer
Shared: Action Roguelike · Action · 2D

Vampire Survivors
Shared: Action Roguelike · 2D · Action

Hades
Shared: Action Roguelike · Action · Indie

Risk of Rain (2013)
Shared: Action Roguelike · Action · Perma Death

War Thunder
Shared: Action · Combat · Free to Play

Cookie Clicker
Shared: Incremental · Economy · Resource Management

BlazBlue Entropy Effect
Shared: Action Roguelike · Action · 2D

Risk of Rain Returns
Shared: Action Roguelike · PvE · Action

Terminull Brigade™
Shared: Action Roguelike · PvE · Action

Windowkill
Shared: Action Roguelike · Action · 2D

Shelldiver
Shared: Incremental · Resource Management · 2D

Shape of Dreams
Shared: Action Roguelike · Action · PvE

The Binding of Isaac
Shared: Action Roguelike · Action · Indie

The Binding of Isaac: Rebirth
Shared: Action Roguelike · Indie · 2D

Rogue Legacy
Shared: Action Roguelike · Action · 2D

Dome Keeper
Shared: Action · Combat · Resource Management

Sephiria
Shared: Action Roguelike · Action · Combat

Rock Bottom
Shared: Incremental · Action · Resource Management

Have a Nice Death
Shared: Action Roguelike · Action · 2D

Spelunky
Shared: Action Roguelike · 2D · Action

Tower Wizard
Shared: Incremental · Resource Management · 2D

Atomicrops
Shared: Action · Action Roguelike · Indie

Dungreed
Shared: Action Roguelike · Action · 2D

FLERP
Shared: Action · Action Roguelike · PvE