Climb! is a platformer entered into the TIGSource A Game By Its Cover competition. The early levels are very easy, but soon the difficulty is ramped up. Your target is to jump from platform to platform to reach a flag each level. After a certain number of levels you acquire a new ability, that allows you to climb walls directly. The only thing that stops you dead, literally, are spikes.
Initially they appear only sparingly, later they are nearly everywhere. Some of the later levels can be a bit tricky to beat, but after you’ve beaten the one pictured above, you shouldn’t have any problems. My first time through I beat the game in under 20 minutes, the second time I only needed around 8, which gives you an idea how short it is. But if you like platformers with precision jumping, you’ll enjoy this one.