Hey! Thanks for wanting to check my game out, I hope you enjoy it. My main goal is to make people laugh at least a little while playing it.
So, to answer your question. I have only used 2 programs for pixel art. Photoshop elements( its cheap and does everything I need) and 2d animation software called TvPaint. I mainly used TvPaint to do all the artwork in my game, mainly because I had the software already and have been using it for the past 6 years to 2d hand drawn animation for my freelance work. I like it more than photoshop because I can do things faster in it. When it comes to text and design type stuff I switch to Photoshop because its easier doing that sort of thing. I haven't used it yet, but I want to try aesprite, mainly because it is built for pixel art but more so because it does circles and ellipses very well at any size, plus its like $20 so you cant go wrong.
For hardware, I use a windows PC i built like 8 years ago, the graphics card isn't awesome but it has 64gb of ram because TvPaint works best with a lot of ram) and a wacom cintiq 22hd (I think that's the model type).
In the end it doesn't come down to the best software/hardware, it comes down to doing the absolute best job you can with what you have.