"Faster Play" only increase by 50% the EXP gain. It allows you to deal faster with the enemies in the early game (especially because the way to one accessory respawns the enemies...) "Faster Play" was, sadly, about a last-day addition before the game jam release, so the thought of making it spawn less enemies didn't occur to me. Will remember that in the future.
The problem with this game is not that we don't want you to explore it, it is more that the characters are here for one and only one reason, and it's not sightseeing. You can finish the game without any upgrades (although you can't really miss Milla's) as part of the characters being only on a werewolf hunt... IF that even comes close to make any sense.
Thank you for your interest in our game, and hope you still enjoy it when you go back at it!