Thanks for playing! I'm glad you enjoyed it!
You guessed it, but checkpoints were dropped due to time constraints, as well as options (mouse sens, input settings, volume controls) and some general gameplay changes for clarity (looking at what shot you during death cam, having a fragment shader zero out the uninitialized back buffer pixels a little more aggressively, that sort of thing). I wanted to focus on (what little) content I could get done, but if I were to put a team on this it would definitely be content heavy; imagining a facility with rooms densely packed and such that full exploration would be viable, and where out of bounds death would be less of an occurrence.
As to your points: I probably could have just had it so letting go of RMB would just teleport you, RMB -> LMB was more a hold over from some ideas I had about how the game might work before it became a stealth game... I was thinking maybe the player would want to no-clip somewhere to gather some information but not teleport to that location, or like a player would want to teleport but only at a specific time so feathering on the RMB would be an option.
I'll look into the itch build suggestion! I want to have the WebGL available to players to play to make it more accessible to players, but I didn't know it affected the desktop app in that way... wondering if there's a way to have it default to WebGL for web users, and PC for desktop app users...?