For me as the developer, it would really help more on STEAM for tonight's launch at 9pm EST / 6pm PST. A review if you like it would help even more, as it makes the game more visible on the platform. But I don't want to pressure either way - I just hope that people enjoy it.
The game is DRM-free on all platforms. The only thing you could potentially miss out on by getting the game on Steam instead of itch.io is the version for Android devices.
Regardless, if you want to support the game and the developer the most, then buy the game on Steam and write a positive review. It helps us reach more customers on the most popular platform for gaming.