I really like the main idea of this! I remember playing a game a long time ago with a similar idea but moving to the right instead of going upward.
This has the potential to be a lot of fun, but at the moment I find it very difficult to hit the block I'm aiming for. Often the closest block above me takes priority even though it appears as though I have a clear shot to the one my cursor is actually over. It would probably be helpful to have fewer blocks in general which would also allow the player to swing around more freely when grappled onto any particular block.
The jetpack seemed pretty glitchy, when it ran out I tried to grapple onto a nearby block but instead I fell a bit and then appeared on top of a block with the message that I'd been respawned.