Subsurface is pico-8 game inspired from metroid. This game is tricky, but the gimmick on each segments make it fun, start from double jump, wall jump, swimming, and even glide. The game also comes with boss battle, and more of secrets to discover.
Extra fact: before I record the gameplay, I tried it first and manage to beat the game with 4 hp (intentionally, you can get 5 hp)
