I really enjoyed it! Congrats, it's a good game and I think it could genuinly be expanded to a full game :)
If you were to continue it, I'd suggest to add either a minimap or a bigger dedicated map that is revealed as you explore the level. Towards the end It's easy to run in circles when you're missing just 1-2 objectives and still have 15 minutes to go.
It might work well as a mobile experience too.