This is the most important section. Googling "50 MB PPSSPP games" leads to shady forums and pop-up infested websites.
The PSP could play PS1 games natively. Those EBOOT files are often 30-100MB without any repacking. Search for "PSX2PSP Eboots" – they run flawlessly. 50 mb highly compressed ppsspp games repack
Track assets are reused heavily.