I feel the same and a lot of the fans here intensify the regret. They will downvote you for saying anything negative about Mike or if you ask for a Steam key. Even if you bought the game prior to the Steam announcement, you are somehow entitled for not wanting to buy the game again.
Allow me to give real criticism then. Both sides have understandable views. People pushed for a Multiplayer update, as well as new content, so the developer decided to indulge them. However, Steam has the tools that Itch.io does not have to make this happen. Steam takes a greater sum of money from developers than Itch does, because Itch defaults at 10% rev cut that can even be changed to 0%. Steam however, takes 30% with no exception. The price increase was inherently necessary for the game to survive on the platform, or Mike would only make cents from it, which would ultimately lead to him abandoning it. Obviously, it makes sense to want your own code for the game if you bought it early, but content creators made the game so popular early on that it could lead to codes for thousands of people, which just isn't a viable option. Personally, as someone getting into Game Development myself, frankly, this game is worth more than the price even after the increase, and is still worth the price tag you would have to pay for both versions. But blaming Mike is really not going to help the issue.