Here is a list all of the materials you will need to complete this project. You can purchase items on your own or you can purchase a kit from me with everything put together that included printed instructions.
Solder Kit
Buy one that includes a soldering iron, a stand, and a solder pump. Bonus if it has solder, wire cutters, or other items that might be listed below.
1 or 2 Breadboards
This project requires a little bit of space so you will want either a large breadboard or two smaller ones. The smaller ones can snap together in different ways.
Pro Micro Atmega32U4 with headers
This is the heart of the handheld. We will connect all parts to it. We will learn to program this to run our games.
I would purchase a few of as it is handy to have one with the header pins soldered on and one without. Also the USB can be pretty easy to snap off.
OLED Display 0.96" I2C 128x64 SSD1306 white
A tiny OLED screen which will be our display. Make sure you get the 128x64 version.
6x6mm Tactile Push Button Switch
You will need at least 6. They typically come in large numbers which is good because they are small, easy to lose and break.
Double Sized Perfboard / Protoboard
These come in all kinds of different sizes and in multipacks. The minimum size you should consider is 5x7cm. 6x8cm and 7x9cm would work great. Make sure they are double sided.
Solder
I used 0.8mm solder for this project. 50g will last you many projects.
22 AWG Solid Core Hook-Up Wire
Getting a kit of this with different colors is very helpful. Make sure it is single core and not multi-stranded.
Wire stripper with flush cutter tool
You will need one of these guys. The little plastic wire strippers that often come in other kits are terrible and don't work. Get this one.