Thanks for the response bolbo. I'll try virtual button controls soon, problem being that i haven't added multi-touch functionality in naalaa yet (but it will work as mousebutton(0 .. n)).
About the sprites. The virtual resolution of the game is 320x240, and i turned of texture filtering to keep the retro feel. Were there other issues than this, like wierd artefacts? If so, please send a screenshot. I've tested the game on a 7 inch tablet, but it has the same resolution as my phone, 480x800.