Hey JeffCube, thank you - glad you liked it!
Yea, the game crashes when throwing a stone when inside a chasm. Throwing a stone inside of a cliff object spawns another stone which collides with the cliff which spawns another stone and so on ... A little bug I didn't get to fix.
We all started together at 2pm on saturday and ended at 5:30 - so 3 hours 30 minutes. At least that is how I understood it.
Even if the hours were counted individually, I took 3h 30 min for programming since Game Maker 2 had issues when compiling to Web that it didn't have when I compiled to windows. Nontheless we're really happy with the result.