km3k: I've tried the same, but have run into lag and audio issues. What settings did you find worked best? I have a Galaxy S3 too.
I still have lag and audio issues but they're minimal. Sometimes the game will 'pop' or stutter, especially when there's no other noises/music.
I'll list the settings I have but I run a custom ROM on my S3 (JellyBam) so it might be more/less capable than a standard S3. I'm also using DoxBox Manager so these are the profile settings:
DosBox Settings:
Memory: 16mb
Frame Skip: 0
Cycles: Auto (anything from 7000-20000 seemed to work, but "auto" worked the best)
Machine Type: svga_s3
CPU Core: dynamic
CPU type: auto
Sound Device: SoundBlaster 16
Audio Frequency: 44100
Audio Blocksize: 4096
Audio Pre-Buffer: 100
MIDI: Off
PC Speaker: Off
XMS Support: On
EMS Support: On
UMB Support: On
Screen and Rotation Settings:
GPU Rendering: No (I found having it set to "Yes" resulted in black lines during cutscenes)
Scale Quality: HQ Scale
Keep Aspect Ratio: Yes
Performance Tweaks:
Turbo Cycles: Off ("On" caused more audio issues with no speed gain)
Turbo VGA: On ("On" and "Off" made no difference)
Turbo Audio: On (The game wouldn't even run without this "on")