This game mechanic is really awesome, and elements of it felt really polished.
Where it missed out unfortunately was the 8 hour gap between having a go. This just felt a little too harsh. The come back mechanic is good, but maybe a few go's before this happens, or maybe less hours.
We also had an issue where if you didn't know the game, you could easily choose to buy the money/currency on your first go, and therefore instantly fail your first room as you have no weapon, and losing your whole 8 hour go.
The practice level was a nice inclusion but even being called practice it feels less 'cool' than the main one. The array of weapond and items were awesome and the game runs very nicely.