Downwell is described as 'curious game about a young person venturing down a well in search of untold treasures with only his Gunboots for protection'. There are nine games similar to Downwell for a variety of platforms, including Windows, Steam, Mac, Linux and iPhone. The best alternative is Tallowmere. It's not free, so if you're looking for a free alternative, you could try Spelunky. Other Downwell like games are Risk of Rain (Paid), Rogue Legacy (Paid), Caveblazers (Paid) and Vagante (Paid).
Spelunky is a unique platformer with randomized levels that offer a challenging new experience each time you play. Journey deep underground and explore fantastic places filled with all manner of monsters, traps, and treasure.
Rogue Legacy is a genealogical rogue-"LITE" where anyone can be a hero. Each time you die, your child will succeed you. Every child is unique. One child might be colorblind, another might have vertigo-- they could even be a dwarf.
Vagante is an adventure set in a dark fantasy world filled with monsters, demons, and crooks. Despite these dangers, adventurers commonly travel these unforgiving lands questing for fame, riches, and power.
Explore, craft, and survive in this Multiplayer RPG Platformer with permanent death! Featuring many Rogue-like elements, Magicite randomly generates each underground dungeon for you and your friends to delve deep into.