I'm considering doing a steam release in the future with proper multiplayer it would be around 3-5$ depending on how much extra content I provide (and whether server cost is a real issue and something I choose to use). I would probably feel the need to improve the visuals a bit and differentiate it a bit more from the original first. Also I'd probably be switching over to steam leaderboards for the steam version for the ability to programmatically create new leaderboards based on whatever settings the player has (up to 10,000 per game apparently)
I'm just working on my physics platformer (like getting over it but it's for controller and you control two arms) right now so my time is a bit split. This is my long term project and I am working on getting a steam page up for it currently and also doing preparations for steam next fest etc