I'll try and find Tetris to test it on my version of MegaMameCE.

When you press the buttons its very strange they act as the Ipaq functions. I had an Ipaq 3970 last year and i didnt have any of these problems, very strange.

As for the screen being larger i'll have to get the rom to test it out. Some games are a bit off screen but i've never had one to this extent you mention

My buttons went crazy, everytime i pressed a button the menu came up over the game. I had configured all the keys but this still happened. In the end Techmaster told me to delete (could be the CFG folder ?) which basically got rid of any corrupt key combinations and reset them all.

Sounds to be the same problem you are having though. Check with Techmaster but i'm sure you delete that folder to get it reset. Hope this was some help