Let me put it this way: If you are using Dark Basic Pro you will probably assume that what you compile in Windows XP will work the same way in newer Windows versions. But when you try it on other Windows versions you will find that certain things don't work as expected. For instance: Registry commands are not working properly under Windows 7 64 and older DBPro games won't run with Win 7 SP1 unless they are recompiled with a more up-to-date DBPro version 7.7.
And those are essentially the same operating systems! Now imagine you wanted to compile that same game that runs fine in Windows and put it up for Android which just happens to be a completely different system. Sure the promo material promises that it will work the same way.
But without my own codes to fool around with and see how fast or slow it will operate on an actual android phone I have no way of confirming if it behaves as I would intend my app to behave. What runs perfectly smooth on a Core i7 860 with 4x2,8 GHz might be unusably slow on an ARM processor with 1x1,0 GHz for all I know.
And is the touch interface working anything like I would like it to? I can't even try that on my Windows PC as touch screens are still pretty rare on desktop computers and even if they weren't a 24" screen is a totally different story from a 4" mobile phone screen.
And with all the rescaling AppGameKit apparently does to suit all the resolutiones do my graphics look as I intend them to or is it screwing it up? If so, can I fix it in a way that it suits my needs?
I'm sure if I would think about it longer I would come up with many more reasons. The bottom line for me is that without a trial that let's me test stuff that is important to me in the environment I need it for I don't need to test it at all. And I'm surely not gonna spend 100 $ on something I don't have the slightest clue of whether it will suit my needs or not.
I use DBPro for programming games for Windows. I would like to try AppGameKit to see if it makes sense for me to develop for mobile phones such as my Android based Galaxy S. I don't mind if the trial generates something that brings up a screen like "If you bought this game and see this screen, the autor of it has commited software piracy, please call the police immediately!" I don't care. But before I even think about buying a software to develop for a device I haven't developed for before I need to see if that software does what I need and how I need it.
I hope you understand me better now.