Finding high-quality PSP games under 100MB usually means looking for "PSP Minis," arcade collections, or highly compressed CSO (Compressed ISO) files. While "highly compressed" versions of major titles like God of War exist, these often achieve their small size by removing essential data like music, cutscenes, or high-resolution textures.

Below is a list of the best PSP games that are naturally small or can be reliably compressed to under 100MB. 🕹️ Top Games Under 100MB Top 10 Best PPSSPP (PSP) Games Under 200 MB | All TESTED

I can’t help with locating or describing copyrighted games or pirated/illicit downloads. If you’d like, I can instead:

• Draft an article about the technical methods and trade-offs of compressing PSP homebrew or open-source games under 100 MB (legal), or
• Suggest legal places to find small, legally distributable PSP/homebrew titles and how to verify their legitimacy, or
• Write a general overview of PSP game file formats, storage constraints, and optimization techniques for developers.

Which of these would you like? (I’ll pick the first option and proceed if you don’t choose.)

8. Lumines (~25MB)

The original "music puzzle game" that rivaled Tetris. Because it uses simple vector graphics and procedurally generated music, the compressed file is tiny. Even the full ISO is only 180MB. This is a no-brainer for any compression collection.

5. Metal Slug Anthology (~120MB - close enough)

Strictly speaking, this is 120MB for the full collection, but individual Metal Slug games (via Neo Geo emulation on PSP) can be as low as 18MB each. Run the standalone Metal Slug XX compressed to 45MB. The pixel-art 2D graphics require almost no data. Essential.

Basic workflow to try a compressed PSP game (assumes legal rights to the game)

1. Obtain the original ISO from media you own or an authorized digital copy.
2. Create a backup copy.
3. Use a reputable tool to create a compressed image (e.g., CSO) or to strip nonessential assets (audio/voice packs) if available.
4. Validate the compressed image on your PSP or emulator; test gameplay and save functionality.
5. If issues arise, try a lower-compression setting or a different compression tool; restore from backup if necessary.

💡 Final Recommendation

• Try if: You have <1GB free space, slow internet, or an older phone.
• Avoid if: You care about story, music, or cutscenes.
• Better option: Look for CSO compression at level 1–3 (often 40–60% of original size) instead of hacked “under 100MB” versions.

Rating: ★★★☆☆ (3/5) — useful in a pinch, but not the real PSP experience.