Nostalgia.GG
Nostalgia.GG is a high quality Game Gear emulator based on SMS Plus.
This is the lite version of Nostalgia.GG. It is ad-supported and some features (manual progress saving/loading and game rewinding) are enabled only when ads are displayed (ie. when you are connected to the internet). We do not want to disturb you during gameplay - no ads will be displayed when a game is running.
* Modern, cool-looking & user friendly interface
* Highly customizable virtual controller! You can adjust the size and position of each button to suit your needs.
* Game progress saving and loading - 8 manual slots with screenshots & an autosave slot. Share save states among your devices via BT, mail, skype etc. directly from the app.
* Rewinding! Got killed by a bad guy? Never mind! Just rewind the game a couple of seconds back and try again!
* Turbo buttons & 1+2 button
* Hardware accelerated graphics utilizing OpenGL ES
* Hardware keyboard support
* Screenshots - easily capture an image of the game any time during gameplay
* Use special cheat codes to make GG games even more fun!
* GG and ZIP file support
Free
I can only find this file as a .XAPK. To install this you will need an app called ZArchiver. You will also have to rename the file and remove the .APK extension (not sure why it is being added when downloading on Android devices).
It will be much simpler to just click the Google Play link and download from there.