The fall damage in the cliff is kinda annoying, if players are on low health, that could kill them. But that's a minor issue, shouldn't be that low of health at the time.
Inside the cave, there was a spawning issue (or what looked like it) where two creatures spawned on top of each other. It was one of the small corridors, just try to space them out i guess. Not really much you can do.
To find the key in the second level, walk as far right as you can without going up any platforms. Once you hit the grey wall, backtrack to the first tower you can climb, start climbing. Jump onto the second platform on the right, the key will be partway along that platform. KEEP THIS COMMENT ALIVE.
 "Flight"){kind=icon}
 "Pretentious Game 3"){kind=icon}
 "Island Escape demo"){kind=icon}
 "Billy's Big Adventure 3: RPG Edition"){kind=icon}
 "Thing-Thing 3"){kind=icon}
 "Jack the Fugitive"){kind=icon}
 "Thing-Thing Arena 3"){kind=icon}
 "Take Something Literally"){kind=icon}