Endless Cave, created by James Pierce, is what you could call a 'progress-em-up'. It plays like a vertical endless runner. Your little character continues descending down the screen and you can only move them left or right. There are gaps between the walls you have to run through. If you don't, you get slowly pushed further up the screen, until you hit the barrier of spikes at the top and it's game over.
It's a suitably addictive game, with fresh dungeon-styled graphics and nice twists on this familiar formula. Baddies patrol the dungeon and if you hit one you'll lose a vital life. Hit too many and it's all over. There are coins and hearts to collect and things get progressively harder and faster the deeper you go.
The levels are randomized, so change each play, and the monsters change in variety too - from slimes and spiders to the lethal turrets. Although somewhat frustrating until you get the hang of it, it's great fun once you do! Soon you'll be regularly delving at least a 100 deep and on a good run up into the 300s.